Rabbi Jack Shlachter (BS '75), Nuclear Physicist and Jewish Community Leader

Centered around Los Alamos National Laboratory, northern New Mexico is home to a small but strong Jewish community, and appropriately enough, one of its key members is the "Physics Rabbi" Dr. Jack Shlachter, a longtime Los Alamos nuclear physicist and leading researcher in fusion studies. In the discussion below, Rabbi Shlachter describes his interest in joining the rabbinate in the middle of his career, and how he has seamlessly blended Jewish tradition with a career in physics - and why there need not be irreconcilable differences that separate science and religion.

Growing up in suburban Chicago, Rabbi Shlachter excelled in math and science, and as a Caltech undergraduate he delighted in receiving a world-class education in physics. His graduate studies at UC San Diego soon led to a research opportunity at Los Alamos, and that in turn led to a professional appointment that has spanned more than forty years. Over the course of his career Shlachter has focused on various aspects of nuclear fusion in both its fundamental research and applied versions. He has also achieved administrative leadership at Los Alamos, and he speaks with pride in having served in a mentorship capacity.

Rabbi Shlachter's path to Jewish leadership is a direct outgrowth of the unique culture of the broader Los Alamos community. He was not particularly connected to Judaism earlier in life, but his involvement in the Jewish community in and around Los Alamos eventually inspired him to delve deeper into Jewish texts, and ultimately, to become ordained as a rabbi. Rabbi Shlachter's approach is to seek discovery in all its forms, whether in nuclear physics or in the sagely perspective of Jewish philosophy, and he is proud to have a role in strengthening the Jewish community in Los Alamos, and providing a religious infrastructure for Jews of all backgrounds. Now navigating a soft retirement that has included an appointment at Brookhaven National Lab and ongoing privileges at Los Alamos Lab, Shlachter's love of science and Judaism continues to grow.

As a special bonus, between Rabbi Shlachter's perspective on Caltech, Los Alamos, and the Jewishness of so many prominent physicists, readers will find fascinating insight J. Robert Oppenheimer and the 2023 film by Christopher Nolan that captured the drama of the Manhattan Project.

DAVID ZIERLER: This is David Zierler, Director of the Caltech Heritage Project. It is Monday, October 30th, 2023. It is my great pleasure to be here with Dr. and Rabbi Jack Shlachter. Rabbi Shlachter, it's wonderful to be with you. Thank you so much for joining me today.

JACK SHLACHTER: It's really my pleasure. Thank you for your willingness to juggle the schedule around so that we could finally get together.

ZIERLER: Absolutely, absolutely. Rabbi Shlachter, please tell me if you have any current titles and institutional affiliations.

SHLACHTER: I do, and when I make presentations I usually list three things, and so I'll give you those three now. I serve as the rabbi of a small synagogue here in Los Alamos, New Mexico, called the Los Alamos Jewish Center. I also serve as the rabbi of a small synagogue in Santa Fe, New Mexico, about a 45-minute drive away from here, called Hamakom. It's sort of a Renewal-ish congregation. I'm also a Guest Scientist at Los Alamos National Laboratory, which means that I can go in, I can check my email, I can go visit people. I don't get a penny of pay for any of that.

ZIERLER: As a proportion of your time and commitments, on any given week, how often are you operating in the capacity of a rabbi, and how often are you operating in the capacity of a physicist?

SHLACHTER: That's a great question. I go into the Lab typically one day a week. I find a talk that sounds interesting or a colleague who I would like to connect with. There are a couple of advantages of going in once a week. Number one, it's my exercise for the day, because I walk from my house to the Laboratory, which is great. Number two, it reminds me how nice it is not to have to go in every single day. If I never went in at all, I would forget that, but by going in about once a week, I'm reminded that it's great that I am no longer full-time employed.

ZIERLER: I want to ask some overall questions about your research and your career, but I want to start with a very timely matter, the unfolding horrors in the Middle East right now, in Israel, in Gaza. Either in your capacities as a pulpit rabbi, as a pastor to your community, or in your advocacy work, are you involved at all in what's going on in Israel right now?

SHLACHTER: Very much so, yes. I don't want to have this become either contentious or political, but I am strongly standing with Israel. I've been very much engaged in—well, certainly in the first few days after October 7th, I helped coordinate a solidarity-with-Israel event in Santa Fe through my congregation in Santa Fe, and I held a similar event here in Los Alamos at the synagogue. I also held an event of the same nature about a week later at a small synagogue in Las Vegas, New Mexico, that does not have a rabbi, and I've been doing a few things with that organization. In addition, we've just set up a community relations council in Santa Fe that is serving northern New Mexico to try to address, with a single voice, the responses to some of the things that have been going on here in northern New Mexico, to try to coordinate messages to congresspeople. So, I've been pretty immersed in it from kind of the activist point of view, though I wouldn't ever characterize myself as an activist. On the more personal level, virtually my wife's entire family lives in Israel, and so every one of her first cousins has children who have been called up in the reserves, and it has been quite a stressful situation.

Perspective on Recent Violence in Israel and Gaza

ZIERLER: What are your takeaways from what is happening in Israel and the response around the world, both for and against Israel, and all of the complexities that that question entails? What have you learned, what are you surprised at now, that you took for granted, perhaps, before October 7th?

SHLACHTER: That's a complex question. I would say I'm somewhat disheartened about the future, in all honesty. I thought we were beyond this, and it is a very sad statement that the world is as dangerous a place as it has been in the past. That Jews are targeted for being Jewish just astounds me every day. The magnitude of this atrocity I think is just incomprehensible. One of my first cousins has a daughter who was spending a gap year in Israel and then spent an additional year because she still wasn't sure what she wanted to do. Her parents, my cousin and my cousin's husband, told her she needed to come back to the United States. She came back probably a month before the atrocities, and I have every confidence she would have been at that music festival. She lost several friends. It just really hits home. I mean, we are not talking about some distant, faceless entity. So it has been very painful.

ZIERLER: How do you make sense of the Israeli response right now and the idea of proportionality both from a self-deterministic national defense perspective and even a Torah perspective? How do you understand Israel's response?

SHLACHTER: One of the things I've often told people is that turning the other cheek is not a Jewish teaching. It comes out of the New Testament. I think we have a responsibility to protect and defend Jewish lives—well, all lives, to the extent possible, but that does not mean simply turning the other cheek. As best I can tell, there have been efforts to minimize the casualties to innocent civilians in Gaza, but it is diabolically evil of Hamas to have placed their headquarters and other infrastructure in a way to maximize civilian casualties. I would say Israel has a more Western philosophy than what is driving what's going on in Gaza, and places human life as a very high value. That's not the case from what I can tell of the enemy. It's very unfortunate for the people who are caught in the middle on that. I understand sympathy toward innocent civilians, but I think what happened on October 7th cannot go unaddressed, and I think the Israeli government, the unity government that went into place almost immediately after October 7th, has been doing as good a job as any moral democracy can do to fight a war. I mean, this is a war. It's not like people don't get killed in wars. Unfortunately there are a lot of people caught in the crosshairs. In the letters that I wrote to my congresspeople early on—and I've subsequently written again, but in the letters I wrote early on, anticipating where this might head, I said, "Thank you for the support you are showing immediately to Israel, but thank you in advance for the support you're going to need to show when the images and the stories start coming out about innocent civilians in Gaza being killed. We're going to need continued support." Because we knew that that was going to happen. I'm not a real expert on this, and I'm not a political analyst, and I'm not a news junkie either, but that's my take on the situation.

The Jewish Community of Los Alamos

ZIERLER: Closer to home, tell me about the Jewish community in Los Alamos and northern New Mexico. How far back does it go? How many Jews are in the area, approximately?

SHLACHTER: Great question. Los Alamos is an anomaly even in northern New Mexico. I know quite a bit about the history of the Jewish community in Los Alamos, less about northern New Mexico in general. Los Alamos didn't even exist as a town until 1943. Fortunately, people now know about Los Alamos because of the popularity of the release of the movie Oppenheimer. Jews came to Los Alamos along with non-Jews, as scientists, to work on the Manhattan Project. Oppenheimer himself was Jewish. Many of the leading scientists who came to the project were Jewish. There was no real formal Jewish community in Los Alamos in the Manhattan Project days. My understanding, though it's a bit fuzzy—I'm not a historian but I've done a little bit of amateur history on this—there's a conflicting minority view, but as best I can understand it, those relatively few Jews who wanted to express their Judaism in some ritualistic fashion went down to Santa Fe during the Manhattan Project period, and they were relatively small in number. I think most of the Jews who came to Los Alamos were largely secular.

After the War, after the conclusion of the War, and the end of the Manhattan Project era, if you will, the Lab could have disappeared, but there was a feeling that there was value in bringing lots of scientists together in one place, which was a novel thing in 1943. Now, of course, the Department of Energy has 17 national laboratories. So, it was a very good experiment, and it was quite successful. The Laboratory went to a low point. It dropped down to a population of maybe only a few thousand from being up in the several thousand numbers at the end of the War. Then, the community grew, because there now was going to be a more permanent establishment. I think it was in the early 1950s that there was kind of the incorporation, if you will, of the Los Alamos Jewish Center as an entity. They didn't have a building at the time, but they either rented space or borrowed space—I don't know exactly what—and they started having regular get-togethers of some kind, so some worship services, some educational events. Then they decided they wanted to build a building. That was probably in the late 1950s. This is an interesting story—they secured a zero-interest loan from the former president of Temple Emanu-El in New York, because that was the largest and probably wealthiest synagogue in the United States. And who had been the president for 10 years? Lewis Strauss.

ZIERLER: Oh, wow.

SHLACHTER: So the bad guy from the Oppenheimer story is the one that they turned to. This is just a guess, but I have a feeling that he was trying to resuscitate his reputation in Los Alamos, because after 1954, his name was mud, and I think that he did this in part for selfish reasons but in part to support the nascent Jewish community. They built the building because of the money that he helped them get. I know this because roughly 20 years later, in 1974, he died, and I found in the archives of the synagogue a letter that was sent to his widow by the president of the Los Alamos Jewish Center, thanking her for his generosity and saying that a donation by the synagogue has been made in his memory to acquire some books for the library in his memory, blah, blah, blah. I thought, "Lewis Strauss? The bad guy from the Oppenheimer story?" I found that letter about a year ago. It's an interesting story. So, he had a very big influence on the establishment of the Jewish Center here in Los Alamos.

ZIERLER: How many shuls are there in the region? Do you have Reform, Conservative, Orthodox, Chabad?

SHLACHTER: In Los Alamos, we have a one-shul stop. It's the only game in town. It has always been sort what one of my friends called "Conservative lite," because that kind of is the common denominator. That has been the only game here in town. It was lay-led for many, many years. There was a guy who was a serviceman—so many scientifically trained GIs were sent to Los Alamos. As part of their military service, they were sent to serve as technicians at the Laboratory. People who had maybe done a few years of college and had gained some physics experience or chemistry experience or whatever but then became GIs, they were sent to Los Alamos to serve as technicians. One of those GIs worked closely with Otto Frisch. He was like Otto Frisch's technician. He stayed at the Laboratory after the War and was one of the real core people behind the establishment of the Los Alamos Jewish Center. His name was Jay Wechsler. He did a lot of lay leadership in Los Alamos in the late 1940s, early 1950s, 1960s. I met him because I came to Los Alamos in 1979, and he was still here, and he was still quite active. I was subsequently ordained, but the synagogue has been here and been non-denominational, if you will, for its entire existence. Often times, it will select a Conservative prayer book just because then you can delete things, rather than using a Reform prayer book and then saying, "Well, we're missing this," or "we're missing that."

So, that's Los Alamos. It's about 45 minutes from here to Santa Fe. Santa Fe is the capital of New Mexico and has a lot of Jews by comparison, though many of them are fairly hidden. My wife likes to joke that people move to Santa Fe because they can escape their Judaism, and they just blend into the New Age-y spiritual aspect of Santa Fe without ever having to affiliate, so it's kind of hard to tell. Santa Fe has two Reform synagogues. It has Chabad. On and off, it has had a small Orthodox synagogue. Now it doesn't have one, but it'll probably come back, because it's like a phoenix, and every several years it comes back again. Then it has this one Renewal-ish group that I am the rabbi of, which is, again, sort of Conservative lite. It's more Hebrew than the Reform synagogues. It's more singing. It's a little more traditional but it's not Orthodox. That's Santa Fe.

If you go about an hour and a half from Los Alamos heading north, you come to Taos, and Taos has a small Jewish community as well. But that's about it for what you might call northern New Mexico. Albuquerque is a little bit of a different part of the state, frankly. That's where the bulk of the Jews in New Mexico are, is in Albuquerque. That's where the population of New Mexico is. Albuquerque has kind of the whole gamut. It has a Reform, it has what used to be Conservative. I don't know that they're aligned anymore, but it's Conservative-like. It has a Renewal-ish place. It has Chabad. It has kind of the whole gamut.

ZIERLER: Perhaps you anticipated my question. I was definitely going to ask you about Oppenheimer. You have so many avenues of insight into the movie. In all of them, how well did the movie capture Los Alamos, how well did it capture the physics of the Manhattan Project, and how well did it capture the Jewishness of the scientists, ranging from both the high German culture that Oppenheimer came from with the more Ashkenazi Lower East Side culture that, say, I.I. Rabi came from? I wonder if you can reflect on all of that.

SHLACHTER: Sure, sure. I love talking about that, actually. I think the movie did a very good job, as a bottom line. I think it captured Los Alamos reasonably accurately. My wife and I lived in New York for a few years, but we came back to Los Alamos in time for when they did the filming, here in town, at Fuller Lodge and other places, at the house that Oppenheimer lived in, so they really worked hard to use historically accurate sets where possible. It was fun to have the film crew here in town. Because it's a big deal in a town like this, when somebody says, "Matt Damon was spotted in the coffee shop!" It was a lot of fun to see all that activity. I think the movie did a good job of recreating what Los Alamos was like. The physics I thought was good. You know, it was a little bit Hollywoodish, but I thought quite good. I think the focus on acquisition of material was very central to the Manhattan Project's success, and the effective use of the fish bowl and the marbles and keeping track of making uranium and plutonium—I have no idea if that was historically accurate, but I thought it was a very effective film technique. And it really did the right thing as far as explaining the physics of what was difficult about the Bomb. The implosion was difficult but also making the material was extremely difficult. Those were well done.

The Jewishness, in all honesty, if you didn't have your ear attuned to it, you might have missed that. It wasn't a central piece of the movie, in my opinion, but parts of it were there. There was a brief interlude between Oppenheimer and Rabi talking about that he didn't learn Yiddish but he spoke other languages. Some of it was there. Look, there's a limit to what you can include in a movie, and I thought the movie did a good job about that. So, it was there, it was a little bit downplayed, but I don't know how central that was, anyway, to the story. I gave a talk about Oppenheimer's Jewishness, and Lewis Strauss's Jewishness, and the fact that they had such different approaches to their Judaism that that may well have been one facet of the conflict between the two. I'm not trying to argue that that was the whole story at all. Obviously, Oppenheimer publicly ridiculed Strauss, and that scene was repeated multiple times in the movie, of him teasing Strauss about his lack of knowledge about the role of isotopes. But I think the Jewishness probably was a piece of it, too.

Latter Embrace of the Rabbinate

ZIERLER: Some overall questions about the trajectory of your career. Now, if I can assume, looking at your educational affiliations—going to Caltech, going on for a PhD in physics—did you embrace a rabbinic interest later in life, or was that always part of your upbringing and you always wanted to merge these interests?

SHLACHTER: No, I think I followed the general trajectory of many Conservative Jews of my era, that I basically hit the age of 13 and didn't want to set foot in a synagogue again after that. It's not exactly true, but it was roughly that. I had a solid education growing up. This is one of those many gifts that I was blessed with. We're going to get to this, I'm sure, later, but it was a real privilege for me to have a career in physics and to go to Caltech, and to have a mind that was capable of understanding physics at some level. I consider that a real gift. I also had a gift of a reasonably good singing voice. That's going to play a role here, you're going to see in a minute. When I was growing up, up to the age of 13, we had children's services and I had the opportunity to lead many of those children's services as the cantor, if you will. I learned the liturgy pretty well, and I was able to lead. That skill laid dormant for probably more than a decade. At Caltech, I had very little connection to my Judaism. I belonged to Hillel maybe for a year. I didn't find it appealing at all. I really was kind of a dropout to Judaism. I would say at some level, maybe in a naïve philosophical way, physics replaced Judaism for me as my understanding of life, if you will.

Then, I went on to graduate school at the University of California in San Diego, and I was there in San Diego for four years. This is now I was age 25. I really still had not done anything Jewishly for quite a while. My thesis advisor, Ralph Lovberg, sent me to Los Alamos to gain some particular skill. He sent me for the summer. I don't think he knew that that would turn into a 40-year career, but that's what happened. So I came to Los Alamos for the summer, not knowing a single human being in this town, not knowing any of the history of Los Alamos. I knew nothing about what Los Alamos was, but I came to learn how to do something. I don't know how I came up with this, but I thought I could do worse than to meet people at the synagogue, because I knew there was a synagogue in town. So I went to the local synagogue, and instantly befriended a lot of people in town. It was a wonderful way to get integrated quickly.

But more than that, there was something about Los Alamos, about the scientists here, about the altitude—I don't know what—but they basically can't sing to save their lives. When I started coming and could sing, people said, "Oh, you have to keep coming. We need your voice. We need you to help lead things. It seems like you know the liturgy. Could you play an active role here?" In addition to finding this letter to Lewis Strauss's widow, I found a copy of the calendar that said that I led a service as early as something like March of 1980. So, I had not been in Los Alamos even for a year and I was already leading Friday night services. So, it's because I could sing that I came back to Judaism. And, there was an influential rabbi, actually. There was a rabbi in Santa Fe, he had some kind of a contract with Los Alamos, and he would come up on occasion, and he taught some adult education classes in Los Alamos. I realized that I didn't know anything about Judaism. My education had stopped when I was 13. I thought I knew everything. Because every physicist thinks that they know everything!

ZIERLER: [laughs]

SHLACHTER: I realized that I was doing things and leading services without any understanding of what Judaism was all about from an adult perspective. I started getting interested. With that arrogance of a physicist, I decided I could learn Judaism. If I could learn physics, I could learn Judaism. You see behind me two of my 60 bookcases in the house. You can learn Judaism on your own, and I really immersed myself, for a number of years, probably about a decade, on my own. Then a rabbi moved to northern New Mexico and he took me on as a private student. My ordination is actually through him, in an unconventional private ordination if you will, but it has not hindered me at all, and it has actually been a wonderful thing to be both a rabbi and a physicist.

ZIERLER: We'll circle back, because I want to see how you've merged them in your career. What kind of physics do you do? What was your degree in, and what kind of work have you done at Los Alamos?

SHLACHTER: While I was still at Caltech, I think in my senior year at Caltech, I took a one-quarter class on fission and a one-quarter class on fusion. Somehow, I got it into my head that fusion was both of great value to mankind and an interesting physics challenge. So, when I was hunting around for graduate schools, I was looking in particular at places where there was an interesting plasma physics slash fusion activity going on. The summer after I graduated, I worked at JPL. I had gotten the job through somebody on the faculty at Caltech, and I worked that summer at JPL. I remember doing some plasma diagnostic work that summer, and also getting a book that was called Plasma Diagnostic Techniques, and one of the chapters was by a professor from the University of California at San Diego. I had it in my head that he was going to be my thesis advisor, and we hadn't even met yet, and he didn't even know I was coming to UC San Diego. I showed up at UC San Diego, I took my classes for a year there, and actually I appealed to the Department that I had taken everything I needed to take because Caltech accelerated the process so much, and they gave me license to go into research immediately, and I started working in this guy's lab doing plasma diagnostic techniques for fusion plasmas. That's what I ended up working on for a number of years as a graduate student.

Then, it was a shift in direction when I got sent to Los Alamos, to look at a particular approach to magnetic fusion. I worked on that at Los Alamos. I actually turned that into my thesis and stayed at Los Alamos as a graduate student for a few years and then immediately became a Los Alamos scientist after I got my degree. I worked on this magnetic fusion concept for about a decade. Then the funding dried up for that. Then I applied some of those techniques to other systems and did work on studying materials under extreme conditions. Then, at some stage—and it wasn't a loss to the world of experimental physics—I became a manager of physicists. Oddly enough, just today, I was talking to the person who launched me in that direction. I hadn't talked to him for ages, but I happened to connect with him and talk to him today. He gave me the opportunity to try my hand at technical leadership. I really enjoyed it. I spent the balance of my career at Los Alamos as a technical manager, ending up both as the division leader of the Experimental Physics Division at Los Alamos and then later on as the division leader of the Theoretical Division at Los Alamos.

Merge Points of Science and Religion

ZIERLER: Now I'm going to ask—it's going to be a very complicated question—how you merge science and Judaism. We can start at the high end. Just as an example, the organization—the Union of Orthodox Scientists. If you're Orthodox, you're going to take Torah literally—whatever that means, "literally." You're going to include Mishnah and Gemara and not just the written Torah, the first five books of Moshe. Then you could go all the way to Reform, which might not necessarily demand of itself a literal interpretation or even the idea that the Torah comes from Hashem or comes from God. Now let's take the physics part of that, the physics which—that there is truth, and there is also an acknowledgement that physicists understand very little about the universe, if we want to take dark energy and dark matter as a shorthand for that. How do you merge these things, for you? Do you have to be a literal believer in order to assert that Judaism and science can work together? Can you simply say there's not enough that we know about the traditions of Judaism that bring us all the way back to what really happened 3,300 years ago? How do you work all of this out in your mind?

SHLACHTER: I'm going to answer this a little bit cautiously because I certainly don't want to insult anybody, you in particular, and I don't know your background or your interest. But I will say that, from my perspective, Judaism is not, even at its most fundamental—maybe at some ultra-Orthodox extremes, but Judaism is not fundamentalist. It is not literalist. I look to statements by, for example, Rav Kook, who was asked about evolution and said, "If that's what the scientific evidence shows, then it's probably right." It may not be the story that we read in Torah, but Torah is not written as a science textbook. It is written to provide us with lessons for life. I don't think there's huge conflict between teachings of Judaism and what physics has uncovered about the nature of the universe. Yeah, I just don't see that we are asked to read the text as a science book. You seem very well-versed, so I'm going to presuppose that you know a lot of what I'm about to say, but the idea that we're each commanded to write a Torah scroll does not mean that with my awful penmanship I've got to go out and get a quill and parchment and compose a scroll. But I think we're each asked to make the scroll come alive, for us, because of our unique history and experiences in life. If physics is one of those aspects of somebody's life, then they must read the Torah with a physics attitude, if you will. That means that when it talks about a day and a night, it doesn't mean that in the sense that we use those terms today, and it doesn't mean 24 hours, and it doesn't mean—there's all sorts of things that when we read the text with the mindset of modern physics, we don't need to read it as if the terminology is trying to teach us physics. So, I don't see the dilemma that might otherwise present itself to somebody who is a literalist. I don't think Judaism ever is intended to be a literalist tradition.

ZIERLER: You say that the Torah should not be meant to be read as a science text. Should physics then not be meant to be read as a religious text? Does it work both ways?

SHLACHTER: That's an interesting question. I don't think physics tries to replace religion. That's probably where I was between—well, I can even go back further. I wanted to be a scientist from the age of four. I'm a product of the Sputnik generation, and I think I got a telescope as a Hanukah present when I was four years old. I wanted to be a scientist from the age of four. I may have thought that physics replaced religion. I don't think that's the case now. I think physics tries to understand, how does the universe work? What are the governing principles that guide the behavior of the universe? It doesn't say why that's the case. And I think Judaism—well, you've already exposed an interesting thing that I haven't completely resolved in my own head—I don't know that I think of Judaism as a religion, in all honestly. Judaism is something different. We try to pigeonhole it to be a religion because there are other things that we call religions that we're familiar with, and so we put it on the same axis. Judaism to me does not fit on that axis perfectly.

ZIERLER: Does the Hebrew word am convey better? Nation?

SHLACHTER: Exactly. A people, or—yeah. A family. That's the reason why I think when somebody Jewish does something reprehensible, we all feel some shame, and when somebody Jewish does something laudable, we feel some pride. It's not a religious thing. It's the fact that we're related. To me that's a very important dimension to Judaism that is probably not there in what we would conventionally call a religion. Having said all that, I think physics is not trying to answer questions of why are we here, or what are we morally obligated to do with our lives. I don't think physics takes a stance on moral issues. Judaism to me is all about morals, and all about how we as—let's take evolution, again for a second—as I understand the science of it, we are evolved from other animals, and in that sense we are the same as other animals and have base instincts and base behaviors. On the other hand, this beautiful passage in the Torah that says we're made in God's image says that we're held to a higher standard and we have the capability of reaching another level that other animals don't have. Judaism tries to teach us how to live our lives at the highest level, in God's image, and not live our lives at the lowest level, as instinctive animals. To me that's what Judaism is all about. I don't think physics touches on that.

ZIERLER: What about the concept of absolute truths, both as they are presented in physics and in the Torah? Do you believe in neither? Do neither actually exist?

SHLACHTER: If I understood the question correctly, you were asking about it in both domains, in, say, the physics domain and in the Judaism domain.

ZIERLER: For example, in physics, there are things that are now understood to be absolute truths, like the Big Bang. Which is funny because Fred Hoyle coined the term derisively because he believed in steady state. Or the apparent un-breakabilty of the standard model. I can go on. There's lots and lots of things that we take as absolute truths, with the caveat that if some experimental evidence comes around, we will reform those truths. It depends on your level of observance, it depends on your culture, but there are certainly some absolute truths that Judaism conveys as well. How do you compare with two?

SHLACHTER: I do agree with you on the science side that we have overwhelming evidence for certain things, and that allows us to make predictions based on these principles. And, should we find that something is not true, we would change it. It's as close to an absolute truth as you can get, but still I think we are always open to challenging those things based on additional data. As far as Judaism goes, that's a good question. I don't know exactly what I would call an absolute truth in Judaism. Maybe help me a little bit and I'll be able to frame my response more articulately.

ZIERLER: Just from the text itself, Torah mi-Sinai, the idea that the Torah was handed to Moshe on Har Sinai, and that it contains 613 mitzvos that Jews, irrespective of our generational detachment from that event, are commanded to perform. I'll give you the standard Orthodox absolute truth.

SHLACHTER: Great, that's very helpful.

ZIERLER: That's a baseline for you to work off.

SHLACHTER: Yeah, that's a baseline. What do I do with that? I use that—maybe this is now just my personal approach to my Jewishness—

ZIERLER: That's all I'm asking for. You only are here to represent yourself.

SHLACHTER: Okay! On almost every topic, I generally tell people there are multiple approaches. We can simply adopt what we are taught without asking questions. This is what we're told—Moses received this on Mount Sinai, we were there, end of story, don't challenge that. That's one approach. Another approach is we can say that served a purpose to have that as part of our tradition when there was a need to feel collectively like a people, but we're beyond that now, and so we throw it out. I can apply that same set of extremes, if you will, to virtually all of Judaism—to Kashrut, to Shabbat, to pretty much everything. What I tell people is, the most challenging but for me the most rewarding approach is to say, we don't adopt it without question, but we don't throw it out because we think it has been replaced by something more modern. We try to incorporate it, with a modern perspective, and we say—for example, with Kashrut, maybe it was put in place because of trichinosis, or who knows what, and maybe it still serves a purpose, because when we take the life of an animal, we should recognize we're on a slippery slope, and if we treat animal life as being basically unimportant, we will perhaps start to treat human life as also being basically unimportant, and that's the wrong direction for us to go. And so by following these prescriptions, not without questioning them but reframing them in a way that allows us to derive spiritual value today, I think we can walk a fine line.

I do the same thing with Moses at Mount Sinai. Did that actually happen? I think there's historical evidence that the Jews were not an identifiable people who left Egypt in an exodus the way the Torah describes it. I think Rabbi David Wolpe kind of broke open the secret about this, that there's very strong evidence that that story is not accurate the way it is depicted. Does that mean we throw it out? No. Does it mean that we adopt it whole-cloth and don't ask questions? No. I mean, I'm a physicist. I ask questions about everything. It drives my wife to distraction that I can't take anything at face value and have to challenge it with a question. But let's take the Sinai experience. What is a message of that? That we're all equal, right? That we were all there. That we had the opportunity to experience revelation directly, without an intermediary. Yes, we call it the five books of Moses, but we actually got to experience it without an intermediary. Then maybe it was too much and we said, "You go up and come back when you've got everything else."

What other message is in there? When I work with people who are on the path towards conversion, I tell them, "When you finish the process, you are full-fledged Jewish like every other Jewish person. You become part of the family. It's not a genetic thing. It's a different kind of connection. Therefore, you were at Mount Sinai along with the rest of us." This idea that it's a living experience, not that there was a historic event and certain people who are now dead were there. It's a living event that we all were there at Sinai. It puts us on an equal footing. It's important, I think, for us to have this shared concept of a revelation that took place with all of us there. That's not a great answer for your question, but it's the way I reshape the stuff that works for me.

ZIERLER: It's a hard question. Rabbi Shlachter, do you put your dual expertise to mutual benefit? In other words, is the logic of the Talmud, of trying to understand what the mefarshim, what the commentators are saying, what the rabbis are saying, does that make you a better scientist? Conversely, does the scientific method, does evidence-based logic, help you understand what the purpose of Jewish texts is, in the way we live our lives?

SHLACHTER: Let me start with the first piece of that. I would say I am a product, either directly or indirectly, of the dialectic approach of text, of questioning things, and that does inform my physics. I think that's the reason why so many prominent physicists are Jewish. Whether they actually were trained in yeshivas or not, they come out of an environment where challenging stuff is part of who we are. I think they, the greats of physics, were better physicists for that. I'm kind of a pale reflection of that. I'm not trying to exaggerate my own physics skills. I was a decent workaday physicist. But I would say that it's not an accident that I grew up wanting to be a scientist and understanding how things work. I think that has kind of been absorbed into Jewish traditions, if you will.

The other way around—does being a scientist inform me when I'm approaching Judaism—a little bit? I like to make analogies, I would say, and I think that having the physics background gives me some tools to help me understand things. We haven't done it for a while now, and I was gone from Los Alamos for a few years and then the pandemic, things changed, but we used to have Torah discussions like once a month in Los Alamos after the Friday night service. And nowhere else I think in the world, except Los Alamos, would the Torah discussions get into so much physics! I mean, it just was unbelievable! Because half the people in the congregation are physicists, the discussions would tend to end up making analogs—is this some quantum mechanical type thing, or whatever. I don't know how helpful that is to the general public, but certainly we had fun bringing the physics in to help us better understand the text at hand. I'll share with you a little bit of, to me, something funny, I suppose. You're familiar with the counting of the omer, and the idea that you can't tell people, "We're going to count the 26th night tonight," because once you've said it's the 26th night, you've already counted it. So, you have to give somebody a hint. Obviously the simple hint is to say, "Last night was 25." That's too easy. So, in Los Alamos, we developed a tradition that we make it as complicated a math problem as we can make it—

ZIERLER: [laughs]

SHLACHTER: —and we talk about prime numbers, and square roots, and cube roots and whatever, and then give people a few moments to try to work out what number we're going to count for the omer. That's Los Alamos. Over the course of time, I ended up with this congregation in Santa Fe, and in many ways, Los Alamos and Santa Fe are diametrically opposite places. You've got New Age and Old Age, or left brain and right brain or something. I mean, they're very different places. I tried this once with the congregation in Santa Fe, and it was a horrible failure! I had people freaking out. One woman told me all her math anxiety kicked in. She couldn't remember what a prime number was. She was absolutely hysterical about it. So, I didn't do that anymore in Santa Fe. But we love to do that in Los Alamos. So there are things that—you gain a vocabulary by having physics at your fingertips, and I think it does help inform us in our Judaism in both minor, trivial ways, and maybe in deeper ways as well.

From Chicago to Caltech

ZIERLER: We could continue on this, but let's now do some history. Let's establish some personal background. Where did you grow up? What was your childhood like?

SHLACHTER: I grew up in a northern suburb of Chicago. I'm proud to say I was born in the city, but my family did the migration that probably 90 percent of Jews did, that they moved to the northern suburbs of Chicago. So, I grew up in a suburb of Chicago, and I went to high school in Skokie, Illinois, so that kind of tells you a little bit about the Jewish environment there.

ZIERLER: How long had your family been in Chicago?

SHLACHTER: My parents were first-generation Americans. Essentially all four of my grandparents came from the Pale of Settlement in the great Ashkenazic wave from 1880-whatever to 1923, they came over. Actually one grandmother was born in the United States but her parents had married in the United States. They came over from the Old Country, so she was just barely born here. I was part of that dominant Ashkenazic Jewish experience of the 1950s and 1960s, and kind of a lower middle class environment. But my father, who was a great influence on me, really set the trajectory early on. My father was the first to go to college. He grew up in Chicago. He lived in the first public housing. His family was quite poor when he was growing up. His father died when he was only nine or ten years old, so his mother was trying to support two small children by herself. It was a very difficult childhood for my father. He was quite bright and went to a technical high school, and then went to college. He went to two years of college and then enlisted in the Army during World War II. He actually served in Europe, and was in the United States on leave being ready to ship out to the Pacific when the War ended. To his dying day, I think he felt that the atomic bomb saved his life. He's one of that era where we could argue that point, and if you're a historian, you know that there's a lot of controversy about that, but certainly he felt that the bomb saved his life. Then he went on to complete his college training as an electrical engineer and worked most of his career as an electrical engineer in Chicago.

My mom's family came to Ellis Island, and she grew up in New York, and then her family relocated to Chicago because of the Depression and because her father was active in one of the garment workers' unions and was able to get a job in Chicago, so she ended up in Chicago. That's where my parents met. My father had a real passion for science, with this interest in electrical engineering and quite a decent mathematics background, but never—the idea of graduate school, I never heard of graduate school when I was growing up. The fact that my father went to college was a big deal. We were all expected to go to college—that was the norm—but nobody ever talked about anything beyond that. I didn't know anybody who had a PhD. I'm pretty sure I never met anybody with the PhD growing up. I was lucky enough that—and we're going to get into this, I hope, in more detail—but I was lucky enough that I got a scholarship that allowed me to go pretty much wherever I wanted to go. I don't think that it would have been straightforward to go to a private school had I not gotten a scholarship.

ZIERLER: From your parents or your grandparents, what level of connectedness did you have to Judaism? You mentioned the standard idea of never wanting to set foot in a shul after your Bar Mitzvah. Was Jewish observance really perfunctory, or did you have a connection to some of the deeper familial connections to Judaism from your family?

SHLACHTER: My parents were actually quite engaged in their Judaism. They were founding members of a Conservative synagogue in the northern suburbs of Chicago. I think it was partly—there was anti-Semitism. My father was denied admittance to Northwestern University because they had a quota. I can remember as a kid, when we would drive past the technical school at Northwestern, in Evanston, he would spit out the window. That was how hostile he was towards the school for denying him admission. So my parents I think felt that synagogues were part of their way to be around other Jewish people and avoid some of the kind of hidden anti-Semitism of that era. My father in particular was interested in what I would call adult Judaism, but somehow I bypassed it. He was almost exclusively self-taught in his Judaism, but he was definitely interested in it, in a way that was very important for me, because I knew that it was a value, and it was not perfunctory for them. I would say it's just that I put all my energy into science for more than a decade before I kind of came back around to the idea that Judaism was more than just something for kids.

ZIERLER: Did you always excel in math and science growing up? Did that very much put you on a Caltech trajectory for college?

SHLACHTER: Yeah. I would say I was destined for math, science things, from an early age. I never went to second grade. I skipped second grade. I was a good reader, but I always had a real interest in math and science. Like I said, it's not a joke that I knew I wanted to be a scientist from the age of four. When I was five years old, when I was in kindergarten, there was a science fair at our elementary school that was really only open to like fifth grade or something like that, and I had a science fair project that I wanted to do that involved a basketball as the Sun, and a ping-pong ball as the Earth, and some kind of scale type thing to show what the solar system was all about. I just was really keen on that, and was fortunate to be able to do well in math and science growing up. Caltech did something very interesting. When I was in high school, they sent a faculty member around to high schools, kind of to interview teachers of prospective students. There was a Caltech chemical engineering professor who came to my high school and interviewed my calculus teacher and interviewed my AP chemistry teacher to find out if I was a good fit for Caltech. It was pretty impressive that he did that.

ZIERLER: Before we leave Skokie—it's out of the chronology, but I want to ask—while we're thinking about Skokie, in 1977, 1978, the famous court case, the controversy about the Nazis who wanted to march through a heavily Jewish town, what was your perspective on that? Were you concerned for your family?

SHLACHTER: No. I was kind of oblivious, I would say. I really was pretty disconnected from my Judaism and from world events. Caltech has both virtues and failings, if you will, or at least for me it did; I was in a bubble in 1976, 1977. Actually I was already out of Caltech by then, but I was still in that bubble of 24/7 focused on physics and science, and really not so aware. It's embarrassing to admit that, but I am admitting that that was just not part of my consciousness.

ZIERLER: In high school, were you enough of a physics nerd that you knew who Richard Feynman was? Was that an attracting point for you to go to Caltech?

SHLACHTER: He was not a name that I was familiar with, but this guy who came to my high school told me that the physics lectures were being given using the three-volume set from Feynman, and he recommended that I get a copy of volume one before going. He actually sent me a copy while I was still in high school. I had a copy of volume one of the Feynman lectures. So, I didn't know who he was, but I knew about him through that volume. No, so I wasn't that much of a nerd, I don't think, but pretty much of a nerd. And really, it wasn't physics. To be honest, it was astronomy. I was going to be an astronomer, from age four. I went to Caltech fully expecting that I was going to major in astronomy. There was a lot of peer pressure at Caltech in the 1970s to go into physics. People said, "You don't want to be an astronomer. You want to be a physicist." I kind of succumbed to that peer pressure, and my target shifted.

ZIERLER: To get into Caltech, did you graduate at the top of your class? Did you apply to Harvard and MIT and Princeton and Stanford, like that?

SHLACHTER: We didn't have a lot of money and it cost money to apply to schools. I kind of had a budget. I applied to the University of Illinois as a fallback school because you could calculate that you could be accepted at the University of Illinois based on your GPA. I applied to two other schools, MIT and Caltech, and that was it. I was accepted at all three. Again, being honest here and admitting some of my own failings of personality, I looked at how far away MIT was from Chicago, and I looked at how far away Caltech was from Chicago, and I said, "I'm going to Caltech." That's not exactly the story, but—I was somewhat rebellious. By the age of 15, my mom was ready for me to be out of the house, and I was ready to be out of the house. Unfortunately she still had to put up with me for a few more years!

ZIERLER: It was 1971 when you arrived in Pasadena?

SHLACHTER: That's right.

ZIERLER: Did you recognize at the time that the school had only gone coed the year before? Did that register with you, that this was so new?

SHLACHTER: It did. Not only was this chemical engineering professor visiting my high school, but there was a guy who was a student at Caltech, I don't remember what year he was in, who lived in the Chicago area, and he came by and visited me during the summer before I matriculated, and he told me about what the situation was, because girls had only been at Caltech for the one year at that point. He told me about going to the Claremont schools, and stuff like that, for social life. I remember him giving me some advice, a priori. My year was the second year that women were admitted to Caltech. I don't know that I was so focused on that when I was applying to the school, but I had a vague awareness of that through these other sources.

ZIERLER: How well prepared were you in comparison with your fellow students, as a reflection of the rigors of your high school education?

SHLACHTER: I was pretty well prepared. I'm guessing that this is still the case, but certainly when I was at Caltech, freshman year was all pass/fail, and all exams were self-proctored. You could take them whenever and wherever you wanted, and there was an honor system that was very important in Caltech life. We got a taste of that early on. They sent us a math exam that was a placement exam during the summer, and you used that exam to figure out what you were going to take for your freshman math class. I remember taking that exam at home in the summer and submitting it, and I was put into essentially second-year calculus as a freshman. So, I had done enough math that I was ready to take second-year calculus when I showed up. I had taken AP chemistry in high school, and so I took an advanced chemistry class for freshmen that was a wonderful class. Really, really wonderful. It was taught by a couple of graduate students who had created their own textbook. We were doing group theory and all sorts of fun stuff. So, I was pretty well prepared coming to Caltech. On the other hand, I had classmates who were miles ahead of me. It was a privilege to be with such smart people. Also it was a privilege to learn, very early on in my life, at the age of 17, that no matter how smart I thought I was, there were people who were a hell of a lot smarter. Learning that lesson early saved me a lot of grief. I think some people struggle with that later in life, but I got to learn that early on.

ZIERLER: The early 1970s, this is still the Vietnam era, civil rights, women's rights, things like that. Was campus political at all? Were you political at all? As an undergraduate?

SHLACHTER: I was absolutely not political as an undergraduate. There was a draft at the time that I was a student, and I remember being driven over to the draft office or whatever it was, the draft board, to register when I turned 18, because I turned 18 while I was a freshman. We had a senior at Caltech who lived in the dorm and drove me over to the draft board. I had a draft number and then they did the selection process, and I did not have to do anything special because my number was fortuitously far enough from what got called in 1972 that I didn't have to worry about it. But I had classmates who left Caltech. I know one in particular who went to Canada for the rest of his college career to avoid the draft. But no, I don't remember anything actively political at all. Or, whatever was going on, I was not part of it.

ZIERLER: Beyond the inclination to do physics and not astronomy, were there any professors or classes that really put you on that track, or even put you on a track toward graduate school?

SHLACHTER: I had an undergraduate advisor who to the best of my knowledge may still be alive. I don't know that for sure. It's Robbie Vogt.

ZIERLER: Robbie is still alive.

SHLACHTER: He was my undergraduate advisor. He was a great advisor, I have to say. He probably helped steer me towards graduate school early on, and basically said if I ever thought that I wanted to do this stuff professionally, I needed to go to graduate school. In addition, he said if I thought I was going to go to graduate school, the time to do it was right after I graduated and not put it off. I think that was good advice that he gave me. I took a full-year class from him as well, but it was really more from his serving as my undergraduate advisor that I gained that wisdom.

ZIERLER: Did you see people like Feynman and Murray Gell-Mann? Were they around? Were they accessible to undergraduates?

SHLACHTER: Yes. Feynman was teaching something called Physics X when I was a student at Caltech, and I would attend some of those sessions and get to see him in action, if you will. Then, very fortunate, my senior year was 1974-1975, and Feynman chose to teach senior quantum mechanics that year. I mean, how—? This is just the luck of my life! It just coincided. He taught that class my senior year, and that was what I was going to be taking as my senior quantum mechanics class. So, I took a full-year class from him as an undergraduate. Very few people can say that, who are around, unless they were part of the 1961-1962-type lecture series.

ZIERLER: Being the early 1970s, all of the revolutions that were happening in physics at this time—grand unification, the building of the standard model of particle physics, the November revolution up at SLAC—were you aware of these things? Were you following the bigger stories in physics at the time? Or this was more of a parochial experience in physics for you?

SHLACHTER: I would say I was not reading the current physics literature and looking at what was happening in the world of physics around me. Feynman touched on some of that stuff when I was taking the senior quantum mechanics class in 1974, 1975, and gave some real-time speculation about some of the discoveries, but beyond that, no. Look, I worked hard at Caltech, and that was so that I could be a reasonable success as a graduating senior. I was not setting the world on fire with my abilities as an undergraduate. I had classmates who were doing that stuff, but it certainly wasn't me.

Plasma Physics and UC San Diego

ZIERLER: When it was time to think about graduate school, where were you considering, and what kind of physics did you want to specialize in for graduate school?

SHLACHTER: I was, again, somewhat limited in what I could afford to do as far as applications go, and so I only again applied to three schools. One was University of California at San Diego, in part because I was used to living in Southern California and that had some advantages, and in part because it had some plasma physics work that I was familiar with. I also applied to MIT because of the plasma physics work. And, I applied to Princeton, because it had a major effort in plasma physics. I was admitted to all three schools, but I think that it was only University of California that could guarantee me a teaching assistantship that would help me support myself as a graduate student, so it was kind of an easy decision.

ZIERLER: Tell me about moving to San Diego and starting up your graduate research. Did you know what you wanted to accomplish, or that really depended on your relationship with your advisor?

SHLACHTER: I somehow had gotten it into my head that what he was doing was interesting, that doing diagnostics of plasmas for fusion systems was an interesting thing. I don't remember even deviating from that at any point. I approached him very early on in my first year as a graduate student and told him I wanted to be working in his lab. He had a somewhat unusual approach to his career, in that he would take on basically one student at a time. It was not the standard hierarchy of a professor and maybe a few postdocs and several graduate students. It was not a big enterprise. He took the more constrained approach of taking on projects that could be done with just a small number of people. He had no postdocs when I joined him. There was one other graduate student who actually left. So, he had two employees—he had a technician and an engineer—and it was me, and him. it was a small operation. But it was good, because you could do a lot of hands-on direct interaction with the professor, not just he was a distant body who was raising money and left everything to the rest of the team. I ended up starting to work for him very early on in my graduate work. I took classes just my first year, as I said. I had basically taken what I needed to take. The deal that I made was that I would not try to get a master's degree. If I ended up leaving UC San Diego not having taken any more classes, they would say I didn't end up with anything. If I got my PhD, that's fine, but if I left I wasn't going to get a master's. I told them I was willing to make that deal, because I was ready to be spending all my time doing research.

ZIERLER: Tell me about developing your dissertation topic. What did you work on?

SHLACHTER: I had worked on something for four years with my thesis advisor in San Diego, and it didn't result in anything successful, if you will. I won't take the credit for it—it was largely his work—but he designed a laser scattering experiment to detect something in plasmas. We detected nothing. We actually transported the diagnostic up to UCLA where there was a small plasma physics device called a tokamak, and we applied this laser to that tokamak, and took data for some period of time, and we didn't see anything. We got zero signal. It's not easy to turn that into a thesis. That was the culmination of four years of work, is that basically we were going to have to start from scratch to do something. My thesis advisor decided that rather than modify the diagnostic, he had gotten intrigued on a different approach to fusion, different from tokomaks. It was work that was going on with somebody he knew at Los Alamos, and it was a z-pinch. It's a different way to approach fusion. It was a very novel kind of a z-pinch. My thesis advisor had worked on z-pinches earlier in his career, and he wanted to go in that direction, so it was quite a change. He sent me to Los Alamos to learn how to do these z-pinches, and the idea was that I would come back to San Diego, we would build a z-pinch like what was at Los Alamos, and that would turn into my thesis. I had been a graduate student now for four years and was starting from scratch, which is not a great system. My thesis advisor had a bad track record. Some of his previous students had taken 10 years to get their PhD. I didn't think that was a great thing, because I wasn't making any money, and it was getting to be problematic.

So, I came to Los Alamos. The intent was to just come for the summer. Instead, here was a working z-pinch, where I could start taking data and do some physics. So, we worked it out that I ended up doing my thesis research at Los Alamos. I spent two and a half years at Los Alamos as a graduate student, working on that working experiment, and turned that into my thesis. It was actually, again, fortuitous, because my thesis advisor had planned to get funding to build a z-pinch, and he ended up not getting the funding, so I would have been high and dry anyway. It worked out really well that I just did my thesis work at Los Alamos. The guy I worked for at Los Alamos was a really nice guy, and a really gentle soul, and a really good boss. He was on my thesis committee as an adjunct, if you will, and he came out to San Diego with me, when I went to defend my thesis. Literally, on a Friday afternoon, I defended my thesis, I was successful, he went out into the hallway—and this is before your time, but this is with pay phones—he went out into the hallway, went to the pay phone, called Los Alamos, called the division leader and said, "Jack successfully defended his thesis. Make him a staff member." I went from being a graduate student on Friday to being a staff member at Los Alamos on Monday. Never did a postdoc. They already knew who I was and what I could do, and it was a great thing.

ZIERLER: Oh, that's great. Was Livermore a player in this space, or this comes later, their work on fusion? Did anybody talk about Livermore? Was there a competition with Los Alamos in this research?

SHLACHTER: Yeah. During the Cold War, people said that our conflict was between the United States and the Soviet Union, but at Los Alamos, the conflict was really between Los Alamos and Livermore.

ZIERLER: I've heard that! [laughs]

SHLACHTER: I drank the Kool-Aid at Los Alamos and had kind of negative thoughts about Livermore. Livermore was not doing a lot in this area of fusion research anyway, so it wasn't a real conflict. Later on in my career, I actually developed pretty close ties with people at Livermore, and it was very successful. I was trying to do some experiments, I couldn't get anybody to be interested in those experiments at Los Alamos, but somebody told me, "Try the people at Livermore. Maybe they'll be a little bit more open-minded about it." I got support for doing those experiments by people at Livermore, and it was a very healthy collaboration.

Los Alamos and Fusion Research for War and Peace

ZIERLER: Los Alamos's interest in fusion research—obviously Los Alamos has a huge component where it's just supporting basic science. There's also the applied aspect of thinking about fusion as an energy source. Then of course there's the weapons aspect. I wonder if you can touch on all three and where fusion research at Los Alamos fit in.

SHLACHTER: The origins of fusion research at Los Alamos go back really to the 1940s and 1950s. Jim Tuck, who was part of the British mission who came to Los Alamos to work on the Manhattan Project, was responsible for the concept of explosive lenses. The idea of having two different kinds of explosives where the explosive wave would go at different speeds and that you could make a lens out of that was incredibly important to the success of the implosion device. He was at Los Alamos starting in the Manhattan Project era. He went on to get interested in magnetic fusion, and he led the magnetic fusion effort at Los Alamos well into the 1970s, I think. He was a presence when I first came to Los Alamos, but I only vaguely remember him attending a few seminars. I don't think he was actively working at Los Alamos when I came. But that program had gone on. It was classified until 1958 or 1959, but that work had gone on for a number of years at Los Alamos. That's the reason that my thesis advisor knew about this work, because his first job after he got his PhD was working in fusion at Los Alamos. That really was magnetic fusion.

What happened—and again, like with the Judaism, you're going to get my spin on this—Los Alamos never bought into tokamaks, and at some stage, there was a collapse of research and the funding dried up for anything that wasn't a tokamak. Probably that was a big mistake, but Los Alamos was all-in on what were called alternative concepts, including this z-pinch idea that I worked on but many other ideas that my colleagues at Los Alamos worked on. My career took a turn. After I had been at Los Alamos for over a decade, magnetic fusion research kind of hit a brick wall and the funding dried up because the Office of Fusion Energy in D.C. decided to put its money into tokamaks. So, everybody had to scramble. If they wanted to stay at Los Alamos, they had to find something else to do. Because the approach that I had been working on for z-pinches involved what's called pulsed power—it was trying to get very high currents very quickly—that technology could be applied to other things, so I segued in my career to working on systems that could put materials into very high-pressure states, because you could apply strong magnetic fields very quickly, and it's the same kind of pulse power technology. So, I was able to get a job at Los Alamos without any interruption. But basically all the magnetic fusion people at Los Alamos found themselves out on the street almost literally overnight because the funding was cut. This approach to putting materials into high-pressure states, I worked on that for a while, but it wasn't too long after that that I started to manage technical people more than to do technical work myself.

ZIERLER: Did the transition from the AEC—the Atomic Energy Commission—to the DOE—the Department of Energy—change your day to day? Did that change Los Alamos at all, during the Carter administration?

SHLACHTER: I don't think it had a huge effect. I think the non-weapons work at Los Alamos had shifted from being, say, a small percentage to being a large percentage, and depending on the administration, that number would wax and wane. I never was directly involved in the weapons program until I became a technical manager and I had people in my organizations who were directly involved in the weapons program. I never ended up doing any research myself in those areas.

ZIERLER: Did you need to get a security clearance? Was that important for your management responsibilities?

SHLACHTER: That's an interesting question. When I came to Los Alamos, it was kind of de rigueur that everybody would go through a clearance process, even if their work wasn't involved in anything that required a clearance. So I think that I got a clearance as a graduate student working on magnetic z-pinches. It just was part of the game at Los Alamos, that if you were a U.S. citizen, you went through a clearance process, without necessarily exercising that clearance in any way.

Supporting and Leading the Los Alamos Jewish Community

ZIERLER: We can now revisit the brief narrative that you already shared with me about your ability to sing and the nascent Jewish community in Los Alamos. When in the chronology does this become something from a passing interest or an irregular commitment to a vocation for you, a new embrace of a new aspect of your interests and responsibilities? When does this happen?

SHLACHTER: That actually was starting pretty early on. I have notes in my files from this rabbi, Leonard Helman, in Santa Fe, coming up to Los Alamos, teaching adult education classes, from the early 1980s. He was pretty influential, because—again, here, the singing comes in. This is interesting. He had a terrible singing voice, and so when he would be asked to conduct a wedding ceremony, he was looking around for somebody who could do the singing. Pretty early on, he chose me as his go-to cantor for wedding ceremonies. He also sponsored me to attend an intensive program through the Reform movement for people who were in communities that didn't have a rabbi and wanted to become more knowledgeable lay leaders. He sponsored me to attend that program. That was in I think 1990. Through the 1980s and early 1990s, I was becoming more and more interested in being knowledgeable about my Judaism so that I could serve as a lay leader, or I could know what I was chanting and not just do it by rote. That was going on through the 1980s and the early 1990s. My ordination came in 1995. I would say the 15 years that I was in Los Alamos leading up to that were a period of pretty increasing interest in Jewish studies for their own sake.

ZIERLER: Did you ever consider or did you take a leave of absence? Was there a part of the ordination process that was so intense that you really needed to devote all of your mind to it?

SHLACHTER: No. That's a simple answer to a question. But it's more that I didn't want to have to give up my physics to do the Judaism. One of the other gifts that I was blessed with, that I consider is very fortunate, is that I don't need a lot of sleep. I was able to devote my energies to my career at Los Alamos without any interruption but also to dedicate a significant amount of time to my Jewish studies, largely self-studies, if you will. But I could do that without having to give anything up. It would have been problematic to take that leave, if you will, because I would have then probably resented things. I wanted to have my cake and eat it too, and I was able to do that, which was really fortunate.

ZIERLER: Besides the geographical limitations of needing to stay local to Los Alamos, which obviously prevented you if you had wanted to learn in a yeshiva in Jerusalem or Brooklyn or something like that, ideologically and temperamentally, when you started to get more into the concept of being ordained, did you already have a good idea of what movement to associate with, or where you would fit in the best, in terms of your own abilities and services? How much thought did you give to that when you thought about, "Who should I work with for ordination?"

SHLACHTER: That's a great question. The plasma physics community, through the American Physical Society, has an annual conference. We, in the magnetic fusion organization at Los Alamos, would attend those conferences regularly. One of those conferences happened to be in Cincinnati, and so I took a few hours out of the conference to go over to Hebrew Union College and meet with the dean of admissions and also to attend a few of the classes. It was actually a very interesting experience for me. The dean of admissions was leaning on me to take that leave and to actually matriculate at HUC, but I attended those classes, too, and I realized, "I know how to learn stuff. I don't need classes anymore, if I want to learn something." That actually helped me make the decision that I wasn't going to go to a seminary and go the traditional route. Much as I probably would enjoy being immersed in Jewish studies, it didn't seem like I had to do that to further my interest in Judaism. And I wasn't about to not be a physicist. That experience was actually quite telling.

The Conservative movement had appealed to me, but again I'm not sure that I wanted to leave physics to do that. I had maybe less interaction with JTS than with HUC, but maybe a little more with the University of Judaism at the time, in California. But again, I just wasn't willing to give one up for the other. Because you're so knowledgeable, I'll throw this in there—it was Rabbi Gershon Winkler who moved out to northern New Mexico, and he in some ways was the ideal person for me, because his ordination was an Orthodox ordination. He was fully steeped in what I would call traditional rabbinic teachings. But then he went off the derech, if you will, and kind of went his own way. That was what I was looking for in a teacher, was somebody whose grounding was extremely solid but who was not going to make the demands of me to toe some line that I wasn't sure I wanted to toe. It just worked out really well that he moved to northern New Mexico and ended up taking me on as a private student.

ZIERLER: What was most important for you, both spiritually and in terms of literacy, to gain, to become a rabbi? Did you want to be able to work your way through a Gemara in the original text? Did you want to be able to answer future congregants' questions about the Jewish position on x, y, and z? What was most important to you?

SHLACHTER: That's a great question. I was ordained in 1995. My children were born in 1992 and 1995, respectively. I wanted to send the message to them—that was one factor—that Judaism was important to me, and I thought ordination was one way to demonstrate that. Maybe more than that, though, I wanted the Jewish community of Los Alamos to have equal footing as any other denomination in town. Los Alamos has a large number of churches, oddly enough, and I wanted the Jewish community to have the respect of the other congregations in town. Without having an ordained leader, I felt that we were always somewhat lacking. So I would say my ordination was more for the external world than for the Jewish world. It was to give a face to the Jewish community in Los Alamos. Like I said at the very beginning, rabbis put their tallises on one fringe at a time. I firmly believe that every adult Jew has both the same responsibilities and the same privileges as every other adult Jew. I really don't treat the title that seriously, except when I'm interfacing with communities where I think that having that title will help the Jewish community out.

End of Cold War and Stockpile Stewardship

ZIERLER: Back to Los Alamos, in the 1990s, when the Cold War ended, did that change things at the Lab in terms of budget, in terms of focus?

SHLACHTER: Yeah. This was the creation of the Stockpile Stewardship Program, because Los Alamos continued to have the same responsibilities, which can be very easily boiled down to the Lab director has to sign a letter every year that goes to the president of the United States that says that the stockpile will work the way it's supposed to work. Now that letter had to be signed without the luxury of doing underground testing. Los Alamos actually developed a robust program in doing things that you could do experimentally that would not violate the Test Ban Treaty, so doing experiments, and doing computation, numerical experiments, if you will, to have confidence that the stockpile was still safe and reliable. So, yeah, funding pivoted, if you will. The test program, which I never was involved in, the test program cost a ton of money, but Stockpile Stewardship then sucked up that budget and people were doing all sorts of experiments that gained you the confidence that the stockpile was what you needed it to be. Yeah, that had a big effect on Los Alamos. In some peripheral way, my research was involved in that, because we had funding through those programs. But then, like I say, by the late 1990s, my focus was now on technical management, not on technical work.

ZIERLER: How close were you to the Wen Ho Lee scandal and the fallout, and then of course as you already alluded, the subsequent creation of the NNSA? What was that like at the Lab?

SHLACHTER: It was a difficult period at the Lab. I think the Lab was in the crosshairs of the public, certainly. The relationship between Los Alamos and the rest of northern New Mexico was never wonderful, and the Wen Ho Lee case, among other things, maybe even more soured the relationship between Los Alamos and the rest of northern New Mexico, certainly, and Santa Fe—the hard drives behind the copy machine incident, and various other things—there was a safety incident at Los Alamos where somebody's eye was permanently damaged by looking into a laser—these things were all negatives, Wen Ho Lee included in all that.

I will tell you, though, that I was here in Los Alamos in 2000, and Los Alamos experienced a horrendous wildfire in 2000. The entire town had to evacuate and it was very traumatic. On the congregational side, I will tell you that for a small congregation with 50 or 60 families, four families lost their homes. It was very traumatic. On the lab side, I was a group leader at the time. Is that right? I'm trying to remember. I had colleagues who lost their homes. It was very traumatic. People evacuated largely to Santa Fe, since that's the logical place to go. That helped turn things around a little bit. I think Santa Fe was more sympathetic towards Los Alamos because of the wildfire, and that kind of erased some of the bad feelings about Wen Ho Lee and some of the other things. I think 2000 was a turning point. I'll tell you that the major synagogue in Santa Fe is a large Reform synagogue, and there's a plaque on the wall that I saw, as recently as probably two weeks ago, that was put up there by the Los Alamos community in appreciation for their generosity and hospitality during the Cerro Grande Fire. I slept on a pew. Now, obviously, people always sleep in the pews, usually during sermons! But I slept on a pew in the middle of the night, because one of our congregants had access to the building, and the Jewish community was able to go into the building at 2:00 in the morning, when we were evacuated. My kids were with me, and they slept on the pews along with us. It was a pretty traumatic experience.

ZIERLER: Was the shul in Los Alamos damaged or threatened?

SHLACHTER: No, but we took the Torahs in our car. My son remembers, to this day, that the first thing you do when you evacuate is grab the Torah scrolls. We did that twice. He evacuated twice. He was eight years old in 2000, and he remembers that we stopped at the synagogue and grabbed the Torah scrolls before we left town. Then he had a little bit of PTSD. He happened to be visiting 11 years later, in 2011, so he was now a college student, but he was home for the summer, and he was with me, and we again grabbed the Torah scrolls and evacuated to Santa Fe. He was a little freaked out, like, "Dad, don't you think we should grab the Torah scrolls and leave town? Because there's a fire, not that far away." So we evacuated before the formal call came to tell everybody in town to evacuate. It happened to be a Sunday evening, and so I thought, "Okay, no big deal. Let's just go." But he remembered that you grab the Torah scrolls. That's the first thing you do.

ZIERLER: To go back to when you were going through the process of becoming ordained, did the Los Alamos shul have a rabbi, or was the idea that you would become that rabbi?

SHLACHTER: They did not have a rabbi. In fact what had happened was the rabbi in Santa Fe, who had been on contract to come up on occasion, he was successful, or the congregation grew up Santa Fe, such that his contract no longer allowed him to come up to Los Alamos. So, Los Alamos was depending solely on lay leadership at the time that I got ordained. There are very gifted people in Los Alamos who did not go through an ordination process but who are very knowledgeable. Los Alamos has always been fortunate to have these very well-educated lay individuals who have to take a leadership role because there's no other game in town. So, it was not even intended that I become the rabbi of the Los Alamos congregation, or at least not to change the importance of lay leadership. I took my turn along with others, but I wanted there to be this outward-facing entity to the larger community. That was really my intent.

ZIERLER: You were probably also capable of doing things that lay leaders could not do, like being involved in conversion and life cycle events. I'm sure that only enhanced and strengthened the Jewish community in Los Alamos, to have an ordained rabbi among them.

SHLACHTER: That's true. But in terms of life cycle events, conversion aside, it's really weddings. Anybody can conduct a funeral service. Anybody can conduct a Bar or Bat Mitzvah ceremony. Anybody can—well, circumcision is a different story, and even as an experimentalist, that's not my forte!

ZIERLER: [laughs]

SHLACHTER: No, but weddings, it's an interesting thing. When it happened that the rabbi in Santa Fe could no longer be called upon to conduct life cycle ceremonies, the only hiccup that I could see was weddings. We came up with a workaround, because starting in 1989 or so, I don't remember exactly when, I was an alternate judge of the Los Alamos Municipal Court, and I started to have the ability to conduct wedding ceremonies in Los Alamos under the auspices of the Municipal Court, with the intent that I could then do a Jewish wedding, should that come up. It never came up. From the time that I started as a Municipal Court judge—for seven years, I was an alternate Municipal Court judge—I never conducted a Jewish wedding ceremony. Then I was ordained, and it was a moot point. But that was my exposure to the municipal political world, by the way. I learned what the Municipal Court judge did. I treated it very seriously. It came into an advantage for me professionally. This is a little bit of an aside, but I was applying for a job as the deputy group leader of one of the groups in the Physics Division, and the group leader had a strange idea that he was going to put the candidates in front of the group and subject them to open questioning by the group members. There I was, in front of the group, along with one or two other candidates, and one of the people asked the question, "Do you actually have the ability to discipline when necessary? We understand you have a reputation as a soft touch. We want to know, if you were the deputy group leader, would you really be able to stand up and discipline somebody if that was required?" And I was able to say, "I have sent people to jail—

ZIERLER: [laughs]

SHLACHTER: —so I don't know about anybody else, but I know I have sent people to jail." That was because I was a Municipal Court alternate judge, and I had sent people to jail!

ZIERLER: Oh, that's great. Was there a regular minyan at the shul? Could you count on a minyan for Shabbos, or it was more like holidays or when somebody needed to say Kaddish?

SHLACHTER: We could count on a minyan for Shabbos pretty regularly in Los Alamos from early on. Then, I think it was a matter of pride for the congregation that if somebody wanted to say Kaddish and it was a mid-week Yahrzeit, we could assemble a minyan without too much difficulty.

ZIERLER: Was everybody connected to the Lab, or are there people affiliated with the shul who are in Los Alamos for other reasons?

SHLACHTER: Let me back up just for a second, because I want to clarify something. Los Alamos, in my time—I don't know about before that; it would be an interesting historical question—but in my time, it always was egalitarian, so counting for a minyan meant including adult women. I just wanted to make that clear. I would say the lion's share of people in the congregation had some connection to the Laboratory, but not everybody. There were families with no connection, but I would say most of the people, from when I can remember, had some connection to the Lab. It's an odd town. You don't just move to Los Alamos because you've heard that it's got a nice climate. I mean, it's an odd town.

Administrative Leadership and Rabbinic Responsibilities

ZIERLER: Professionally, moving into technical management, not working day in and day out on the physics, the science itself, did that work for you? Now that you had these dual responsibilities as rabbi, was that a nice balance?

SHLACHTER: Let me answer the question before I get into the rabbinic piece. It worked well for me scientifically because, as I say, the world of physics did not suffer greatly when I stopped doing hands-on research, but I really got tremendous vicarious pleasure out of learning what my group members or division members were doing and helping to promote their work. I think that I was an effective spokesperson because I could translate their work into more generic terms and be maybe even more effective than they were at selling their work. I really enjoyed doing that, and I really enjoyed getting to interact with smart people. From the day I started at Caltech to today, I've had the privilege of spending my life with smart people, and it's really a privilege. I mean that. Sometimes I have to interact with the real world, and I say, "What a bunch of idiots," right? Really, it's a privilege to work around smart people. I considered myself very fortunate to be a technical leader of smart people whose work I could then learn about and help promote. That's that piece.

The Judaism piece, I don't know how that entered in one way or the other. I mean, I worked hard. When I worked at the Lab as a full-time employee, I put in more than my share of hours. Certainly, when I was the division leader, it was a demanding position, that especially with email and remote work, it never turned off. I'll just give you some numbers. As the leader of the Theoretical Division, which is the last position I held at Los Alamos, and I had that position for four years, I had 200 scientists, 100 postdocs, and 100 support people working for me. That's 400 people. Then in the summertime, we had students as well. There was always some issue, and I mean always, 24/7, something was going off the rails that I needed to pay attention to. I devoted my time as best I could to keeping the Division in good shape. I think my rabbinic work was always kind of a side job, and I knew that that was what it was. I don't think anybody expected that I would drop everything, unless it was a funeral or something like that. The Judaism had to be compartmentalized. I did my study and my preparation in odd hours, because as I say, I could get by with not a whole lot of sleep. But I did not shortchange my Lab job at all. They got their money's worth from me. The Lab treated me well, too—I'm not complaining—but I had a lot of responsibility with the number of people.

I'll tell you just an anecdote, because I always enjoyed this one. I had the deputy division leader position in the Theoretical Division for five years. It was a wonderful job. That was really an easy job, because the buck didn't stop with me. I got to find out what was going on in the Division and do what I wanted to do. It was a really great job. The division leader said he had really not had a good vacation for a long time, and once I became his deputy he felt comfortable that he could disappear. So he took, I don't remember if it was a four-week vacation or what, but I was acting division leader for four weeks, let's say. The second day I was in charge, I get a phone call—and it was summertime, so there were a lot of students around as well. My division leader went on vacation, summertime, a lot of students. I get a phone call the second day from one of the group leaders—some student has been taken to jail, and we've got to bail him out. I mean, it's like, where did this come from? I don't remember training at Caltech for how to bail somebody out of jail. We resolved that issue. Two days before my boss came back, another group leader called and said one of his students was taken to jail, and we had to bail him out. My division leader thought it was the funniest thing he'd ever heard, because I don't think he ever had to bail anybody out. But that was the demands of the job. If something happens, you have to respond. By the way, it wasn't serious stuff. Students come, their driver's licenses are from other states, because they're almost always from elsewhere, and if they fail to pay a parking ticket or a speeding ticket or something, there's a bench warrant on their license. Now they come to Los Alamos, and if they get pulled over for a taillight or something, they run a check on the license—well, there's a bench warrant out, and off the person goes to jail. So, it wasn't so serious, but we didn't want them to languish in jail.

A Soft Scientific Retirement

ZIERLER: You mentioned right at the beginning of our talk that you are down to one day a week at Los Alamos. When did you start thinking about a retirement, or a soft retirement, as it were?

SHLACHTER: I did a semi soft retirement by leaving the laboratory when I hit the 40th anniversary of my hire date as a graduate student. I hired on in June of 1979, and in June of 2019, I said, "You know what? I've been division leader for four years. It's going well. That's a great time to end." But I didn't really want to stop working full-time. What happened was I got this job offer to work at Brookhaven National Lab, so the semi soft landing was to leave Los Alamos but to work full-time at Brookhaven. But I had zero people working for me at Brookhaven. The responsibilities just did not seem anywhere near as demanding as division leader in Los Alamos.

ZIERLER: Perhaps this was the postdoc that you never got to do right after you defended!

SHLACHTER: It could be, but nobody said there was going to be a pandemic during that postdoc! So, the Brookhaven experience had its own challenges, most of which involved working from a closet. That was the way it turned out. Anyway, I worked for two and a half years at Brookhaven, and that actually gave me the distance that I needed, partly because of the pandemic. I wasn't interacting with people face to face on a daily basis. So, when we came back to Los Alamos, it still took me some time to adjust, but I managed to adjust.

ZIERLER: You're still with Los Alamos? You love it so much you're still not ready to let go of it entirely?

SHLACHTER: I like science, very much. It was not a hardship to be working in science. It was a joy. I have a talk scheduled tomorrow that I'm going to attend because it just looked interesting, and I have the luxury to just go and drop in on that presentation and see some colleagues and find out what they're working on. The people in T Division were wonderful. I really loved being the division leader there. I still want to know what they're working on even though I don't do hands-on work.

ZIERLER: Now that you are in semi-retirement, does that give you opportunity to do things as a rabbi, even travel, even interact with Jews beyond northern New Mexico, that wouldn't have been possible earlier in your career?

SHLACHTER: Yeah, they would have been definitely harder earlier in my career. I can now pick up and go without any worries about what's happening at the Lab. When you and I were first interacting, I had gotten this opportunity to lead High Holiday services in Warsaw, Poland, so my wife and I were in Warsaw from September 10th until September 27th. it was an amazing experience. I won't say it was all a positive experience, but it was a very fascinating experience, and I never had to worry, "What's happening at the Lab, and what fires do I need to put out there?"

ZIERLER: Is there also a mirror image semi soft retirement as rabbi in Los Alamos? Is there a next-generation rabbi, or are you still where you were when you started?

SHLACHTER: That's a great question that I don't remember anybody asking. Yeah, I think I would love to continue doing rabbi-ing as long as I can. There's the Talmudic statement that you learn more from your students than from anybody else, and I believe that. And, I love to teach, and so I hope to continue serving as a rabbi in one capacity or another for as long as I'm able to do it. I'm a real addict of buying books, and it gives me an excuse that I use the books to put together a talk or to learn some topic. One of my congregants last Saturday asked me, "What does Judaism say about taking the life of another person, even if it's in war?" I realized, this is as current a problem to address as any, and I said, "Let me do some research on that and I'll get back to you." That's what I'm putting together right now, is a talk about the Jewish stance on taking a human life and under what circumstances is that permitted, or even required. I think it's a very contemporary topic, and a very deep topic, and one that I get intellectual satisfaction out of doing the research to address that.

Maimonides as Plasma Physicist

ZIERLER: Now that we've worked right up to what you're doing now, for the last part of our talk, if I may, I'd like to ask a few broadly retrospective questions about your career and then we can end looking to the future. Just to stay on the theme that you're conveying so beautifully now that you never stop growing, and that's true as a scientist and as a rabbi, I wonder if you can reflect on what both of these aspects of your professional life and spiritual life, really, that you have learned about self-improvement? What are the big lessons as a scientist in the art of self-improvement? What are the big lessons in Judaism and being a rabbi in self-improvement for you?

SHLACHTER: Let me start with one of my rabbinic heroes, and that's Maimonides. I always joke that if Maimonides had lived in our era, he would have been a plasma physicist and a rabbi, not a medical doctor and a rabbi. Maimonides says that Judaism generally approaches things with a middle of the road kind of Aristotelian approach, that you don't want to be celibate but you don't want to be profligate. You don't want to be a glutton but you don't want to be an ascetic. He says there's one virtue, or one characteristic, where you can never go too far, and that's humility. When you think you're in the middle of the road on the humility scale, you're probably being a little too self-aggrandizing. I think that this is an important piece of what I continue to learn from Judaism. Because physics can lead to a lot of arrogance, and I have managed to know a lot of pretty arrogant physicists in my day. I think Judaism kind of gives the humility that's needed in order to really excel. I will tell you that I got to know Willie Fowler when I was a student at Caltech, and I think he, more than any other Nobel Prize winner that I've ever gotten to know, was a humble, brilliant physicist. Maybe that's the goal, right? It's to bring some of that recognition that there's always more to learn, and that you can never be too humble. If you start to think you're pretty humble, you're probably not there. And you don't need to be arrogant. I think somehow that is part of my answer to your question.

ZIERLER: How important is Kiruv to you, both in the scientific sense and then purely in the spiritual sense? Kiruv, of course, the idea of bringing people closer. In science, culturally, I think—maybe you'll agree or disagree with me, but I sense that there is a strong bias not to be—at least outwardly spiritual. That if you're a serious scientist, that must mean, or it mandates, that you're not a believer, or you're not religious, or things like that. Have you ever, either by example or just seeing people with latent interests, have you ever sort of conveyed the message, as we were discussing right at the beginning of our conversation, that there's more compatibility here than meets the eye? Your own life experience is testament to that. I wonder if you've ever engaged with fellow scientists along those lines, Jews or non-Jews.

SHLACHTER: Not so much, to be honest. Let me back up a little bit. What is it that I like to focus on with my rabbinic life? I serve congregations. I do the normal things that rabbis do. But what do I really have a passion for? It's exposing adult Jews to the beauty of Judaism that I fortunately discovered almost by accident. I like to expose other adult Jews to that same beauty. I don't know that that necessarily is spiritual in the conventional sense. I certainly don't dwell on theological issues. I think Judaism has much to offer adults about how to live our lives. If I have any passion in my rabbinate outside of the normal rabbinic activities, it's exposing adult Jews who also probably reject Judaism and particularly here in Los Alamos—with a lot of scientists who say Judaism is some archaic thing, and I don't really need that, I like to expose them to what Judaism means to me, not theologically but just from the point of being a better person. That's maybe the Kiruv that I try to do, but I'm not out there proselytizing as such.

My wife assists me a lot in my rabbi work. She's a wonderful behind-the-scenes person. She helped me put together a series of three talks that I gave over the last few months. As if it wasn't busy enough, right? But I gave three talks that were broadly advertised in Los Alamos, through the public media, that were like an introduction to Judaism. My target audience mentally had been Jews who, like me, kind of thought that they had outgrown Judaism, but I think they think that erroneously, for lack of knowledge. That was my real target audience. It turns out that we did have a reasonable turnout for these three classes. The target audience wasn't quite what I expected. There's a lot of people out there, and maybe in hindsight I should have realized this, people who are not Jewish but who now have Jewish relatives, either a child married somebody who's Jewish, or they have Jewish grandchildren, and they want to know, "What is this thing that seems to be important in the lives of people who are important to me?" So, we kind of pivoted a little bit with those classes. But that's really what I'm trying to target, and I would imagine, doing that kind of thing in Los Alamos periodically, which I think we will be doing, it will naturally touch on the scientific community, because that's Los Alamos, right? But I'm not out there hustling it in a real active way. But if I could leave any message with—I mean, Jews are really who I care about, in the end—I would love for adult Jews to realize there's a lot more beauty in Judaism than you may have been led to believe. I guess that's what I try to do.

ZIERLER: In sharing the beauty of Judaism with people who don't have a strong cultural or knowledge base, have you encountered people that naturally incline and want to become observant? Do you have the rolodex or the connections where, if this is something that people want to pursue, you're encouraging of it and you know where to send them? Because obviously they would need to leave Los Alamos. Have you ever encountered that?

SHLACHTER: There have been people who have done exactly what you say. They have left Los Alamos. Largely it's because there's no day school here, so if they end up where they are really immersed in their Judaism in a way that says that their children need to go to a Jewish day school, they are definitely not staying in Los Alamos. It hasn't come up enough that I would say I have a full rolodex on that, but I don't think I would be too nervous about, could I figure out where to send somebody. I think I have enough connections built up over the years that I think I could help somebody on that path. The hope is that they wouldn't have to leave Los Alamos. You can be observant in Los Alamos. You can't raise a child in a day school in Los Alamos, but you can be observant in Los Alamos. It's a small fraction, but we've had people from time to time who are really Torah-observant Jews. It can be done. If anything, it's the modern Orthodoxy approach, that you can live in the world of the science of Los Alamos without giving up your Judaism. I would hope that's the case. But if somebody says, "I really can't see how to do that"—my wife and I are vegetarian; that solves the Kashrut problem pretty quickly. It's a walkable town, and the shul is a 15-minute walk, maybe, from our house. It's not impossible to be here and to be observant. But it's not something that comes up very often.

ZIERLER: At work, on Lab, have you assumed the persona "Physics Rabbi"? Do your colleagues associate that? Have you ever gotten trouble—not from an anti-Semitic perspective, but like a, "Really? Are you serious?" kind of perspective? Have you ever dealt with that?

SHLACHTER: I haven't had any problems with it, and I definitely do not hide my Judaism. People are well aware that I am Jewish and that I'm a rabbi. I will tell you an amusing thing. My wife Googled something one time and found an article that said I was the "Rabbi of the Los Alamos National Laboratory."

ZIERLER: [laughs]

SHLACHTER: [laughs] We happened to be at a—it was one of those dinners in conjunction with an external review committee, so it was a committee that had come in to assess the health of the Theoretical Division, and I was the division leader, so the Lab director was at this dinner. My wife and I are at the table with the Lab director, and she told him this story, that I was the "Rabbi of the Los Alamos National Laboratory." He thought it was pretty amusing, too!

ZIERLER: [laughs] Let's return to the thing that brought us together, of course, which is Caltech. Have you been an active alumnus over the years? Are you connected with your former classmates? Have you ever come back to Pasadena for various campus events?

SHLACHTER: Not a super active alumnus. My wife and I had the good fortune to accumulate what for us was a reasonable amount of money. Hopefully we'll have other opportunities to be generous in our giving, but we felt strongly that giving to Caltech was on our list, and we endowed a scholarship at Caltech in my parents' memory. The idea was to target somebody who was a first-generation college student, because my father had that experience, and I thought that that made sense. That was a close connection to Caltech, because we had come into some money. The reason we came into money, by the way, is because I got a full-time job at Brookhaven but I had retired from Los Alamos with a generous retirement salary, so for the two and a half years that I was at Brookhaven, I had two incomes, and we definitely did not need that to live on.

There was one period in my career at Los Alamos where I was trying to promote experiments on a facility that we were in the process of building. This facility was going to allow you to do—I've mentioned this before—experiments on materials under extreme conditions. To me, the pinnacle of my career, in some ways, was being invited to give a talk at Caltech on this topic. I only did that one time, I only gave one technical presentation at Caltech as a PhD, but it was really a high point for me, to come back to Caltech and to give that talk. And, I have to tell you, Steve Koonin was at the time I think maybe the provost, or I don't know exactly what his position was, but he would scan the list of what talks there were, and he dropped in on this talk. I thought, "Okay, he was a senior when I was a freshman at Caltech."

ZIERLER: Oh, wow.

SHLACHTER: It was a big deal for me that I gave this talk and he dropped in on it. But I haven't had a close connection with Caltech. I don't keep up with a lot of the people from Caltech. My freshman roommate from Caltech went on to have a very distinguished career as a professor at Southern Methodist University at Texas. He retired a few years ago and he moved to Taos, New Mexico [laughs]. Now, it's like going full circle. We had shared a room as freshmen, and now he's living up in Taos. So, I have a connection to somebody from my earliest days at Caltech, not too far away, but other than that, no, I haven't actually been real active with alumni activities.

ZIERLER: In reflecting on your education at Caltech, and also just the culture, the society of Caltech, learning what it means to be a scientist, what has stayed with you? What has remained close for all that you have achieved in physics and in science?

SHLACHTER: Maybe to bring Judaism back into it, I think the idea of asking questions, no matter if you're a starting freshman or you're a senior faculty member, asking questions was the Caltech way. Then I go back to that quote attributed to I.I. Rabi, that he said his mother would say, "Did you ask any good questions at school today?" To me, that was the Caltech way, and that's the Jewish way. That has stayed with me. Like I said, my wife sometimes gets frustrated with that attitude, but I think it's so important, both in science and in Judaism, that we ask questions. That's how we learn.

ZIERLER: Finally, Rabbi Shlachter, that's a perfect segue to my last question, looking to the future. We can bring up the topic of Ain Sof—there is no end—and that's equally true both in one's relationship to God or to Jewish learning, and to scientific discovery. For you, for however long you want to remain active in both of your capacities, what do you want to accomplish? What do you want to continue doing that you have not fully accomplished yet?

SHLACHTER: I guess on the science side, this is a little bit of a joke, but I would say that fusion was 30 years in the future when I entered the field, and now it's probably 40 years in the future. So I'm not sure that I helped the profession out too much!

ZIERLER: [laughs]

SHLACHTER: But I would love to see fusion become commercial, not just a demonstration of inertial confinement at NIF, at Livermore—

ZIERLER: You're talking about what we saw this past December?

SHLACHTER: —yes, exactly—but something really on a path to commercialization. I think that would be great. I really think that energy is a huge player in what the world can do. Energy resources drive a lot of the instabilities in the world. I think fusion—I believed this from the time I went into it when I was a senior at Caltech taking a class from Roy Gould—I believe that fusion really does offer the world something that nothing else can offer, so I would love to see that move forward. As an interim, by the way, I happen to be a proponent of fission, and I think we are making a huge mistake by not putting more effort into fission as an energy source. I would like to see energy become available to people who don't have access to it, and I think there are some scientific paths to getting there. On the scientific side, that's what I would like to see. On the Jewish side, I would love to see more adults go down this path of rediscovering or discovering for the first time that Judaism has a lot of wisdom to offer. It's not just something for kids and you drop your kids off at Sunday school and then go skiing. I think there's really something to this. It has been around for a long time because it appeals to intellectual, sophisticated people, not because it's something useful for children. I would love to make some progress on that front.

ZIERLER: This has been a wonderful, truly unique conversation for me, and great for Caltech. I want to thank you so much for doing this.

SHLACHTER: Oh, the pleasure is mine.

[END]