Interview with Dr. John F. Zasadzinski

JHT:

So I suppose I'd like to start where you started – that being with your experience with physics, what your relation with physics was before college, particularly with your family, but really anything before college.

JFZ:

So I'm from Chicago, not too far from IIT, and it's a blue-collar, working class community. I was the first one in my family to go to college, and most certainly the first one to go to graduate school. So, my background was nothing special. It's not like we had a lot of books in the house on science, but I was good at math and science in grade school, and in high school I was pretty good at physics and math as well. Then I went to Benedictine University in Lisle, which is a small, private college. At the time I didn't know whether I would be good at physics. I think when you go into college, you're not sure how you're going to compete with other students, but then I realized that I was starting to get the material and then by the time I was a senior, my advisor was recommending going to graduate school and so I applied to only two places: University of Illinois and Iowa State. I got accepted to both but I picked Iowa State, simply because I thought I'd be more comfortable there. It seemed like a smaller university, so I got my PhD at Iowa State. Do you want me to keep going?

JHT:

I would say it'd be good to focus on just the undergraduate experience and if, at the time before going into your PhD program, you had known what topic you were interested in studying.

JFZ:

No. We just studied basic physics – your standard physics curriculum: quantum mechanics, electricity and magnetism. I also double majored in math. I started out as a math major and then switched to physics and then I had enough credits to get a second major in math, and so I would say that the curriculum gave a really solid foundation in basic physics, but I had no idea what I was going to do. I think nowadays, students often are already starting to think that they want to do theoretical physics or experimental physics, but I was sort of a blank-slate, just waiting to see how things worked out. So I did not know; Actually, I was interested in astrophysics. I think everybody's interested in astrophysics. Why would you not be interested in astrophysics? But there weren't any jobs in the field, and so I knew that when I went to graduate school that the best area to work on for getting a job – I thought I might end up with a job in industry, so solid state physics, or what they called condensed matter physics, offered the most opportunities. At that time, this is the late '70s and early '80s, there were famous U.S. corporate research labs, which you don't see too much today. Probably the closest thing is Google. Google has its own basic research labs now for quantum computing, but at the time places like Bell Labs, which was the national phone company, AT&T, was the best lab in the world, but places like General Motors had their own corporate research labs...Westinghouse, Ford. So there were lots of industrial jobs and most of those were in condensed matter physics, so it was a very practical choice, but I think it turned out well.

JHT:

Apart from the practicality of it, were there any courses during your undergraduate years that may have scared you away from physics, or contrarily ones that really inspired you?

JFZ:

I just remember the pace of courses being slower. The material that you cover in three semesters now in general physics, we covered in four. We dug a little bit deeper, but I thought we got a better grounding in physics. I get the sense that the way it's done now it's fast paced and the students are sometimes having a difficult time keeping up with the pace. I didn't feel that at the time because we did it over four semesters. So no, I never felt overwhelmed by the courses I was picking, so I never thought of leaving physics and doing something else. It was my skill and I decided just to run with it, see where it took me.

JHT:

So then, when you entered your PhD program – students are always told now that they should research the universities they're applying to just as much as they research physics – did you have an idea of who your advisor would potentially be?

JFZ:

No. They encouraged us to spend time with the different research groups that were there, so my instructor in solid-state was David Lynch, who was an optics guy, and so I started doing optics research. I didn't like it too much, so I had a faculty member teaching me quantum mechanics and he was an experimental condensed matter physicist. So I started working with him and that was in superconductivity, which I thought was cool, that you'd transfer liquid helium and you were measuring things down at one degree Kelvin, so I just thought that was more interesting and I got into that. But then he took a position at the Department of Energy as a program director for a few years and so I transferred to another faculty member who had just arrived on campus, so I was his first PhD student, and so it was just he and I putting the lab together and it turned out to work really well.

JHT:

Who was the faculty member that left?

JFZ:

Doug Finnemore

JHT:

And then you went to?

JFZ:

Ed Wolf

JHT:

What was your relationship with Dr. Wolf like?

JFZ:

I thought it was good. I had to build some electronics and I remembered an experience back as an undergrad. During the summer, a faculty member asked us if we would build some power supplies for the physics lab. So there were three physics students. We spent a few weeks on campus and they had something called Heathkit. You could build your own audio amplifier. It was just electronics. You could build your own electronics equipment for about a third or fourth of the price of what you would pay for if you bought it already built. So, we were building power supplies and that's where I learned to solder, to drill holes into metal cabinets, to make a circuit board, and things like that – that experience gave me courage – Then I bought an audio amplifier and at that time the cost was pretty high. A good audio amplifier, one-hundred watts, was around $250, which was a lot of money back then and I could get the Heathkit version for seventy dollars. So I bought that and built it. It took me two or three weeks to build. I carved out a table in one of the physics labs. I didn't think it was going to work. When I plugged it in and pushed the button, the power light went on and then I had an amplifier playing through our stereo system.

JHT:

What was the environment at Iowa State like during your time there?

JFZ:

It was great. The environment was great because there were no distractions. Ames Lab is in the middle of farm country in Iowa, so I didn't have the distractions that I would have had if I stayed in the Chicago area. So, it was great; We focused on our classes, doing homework, and learning as much as we could.  Then being in a lab, it was nice and quiet at night. I would go back at night and do my experiment and it was great. The people were great. I made friends in graduate school. Everything about it was enjoyable.

JHT:

Were the disciplines of research there diverse or mostly focused?

JFZ:

There was theoretical and experimental physics. We had a reactor on campus, so they were doing an experiment called neutron scattering right on campus. A lot of students went into that, but I didn't like that – I wanted to just build my own lab, my own equipment, and my own setup. I just wanted to have my own thing. When you're doing neutron scattering, there are technicians, you're part of a group, and you're just doing one slice of the experiment. I just preferred doing things myself.

JHT:

Has that style remained throughout your career?

JFZ:

Yes. My groups have generally been small. Now that I'm affiliated with Fermilab, I was on a paper that has thirty authors. That was the first time I've been on a paper with that many coauthors, so that's something new for me. Typically, the group when I was at Argonne, our group had two staff scientists, myself, and maybe another graduate student or postdoc working on the research project. I liked it that way. 

JHT:

Would you say it's becoming more popular to have these very large research groups and publications?

JFZ:

Yes. If you look at some of the national facilities, for example LIGO, or any of the detector projects affiliated with particle physics research, there could be 250 authors on a publication. How do you know who did what? It's hard. But my first publication was just my advisor and me. They spelled my name wrong, so I got my first publication and my last name was spelled wrong. Then we had a theorist work with us so there were just three of us on the first few publications. That was great because then I got to present my research at conferences and that helped my career a lot.

JHT:

Bringing up your last name, might you know where it comes from and the role culture played in your family?

JFZ:

Well, Chicago is a collection of ethnic neighborhoods. Maybe not as much now as it was back in the '50s and '60s. The neighborhood I was in was predominantly Polish, but it had a few Irish and Italian people as well. I'm second generation, so my grandparents were immigrants to the US, but I don't speak the language. I can pronounce a few words, but I don't really speak Polish. But that certainly had an influence on my childhood. Most of my friends were Polish. Everybody pronounced my name correctly. It was only when I left the neighborhood to go to high school that people struggled with my name.

JHT:

Is this the area just south of Wicker Park?

JFZ:

It's actually 38th and Ashland, which is not too far. Now there's a microbrewery on 35th close to Ashland and so that is the near South Side.

JHT:

Going back to your PhD experience, before your thesis or perhaps the thesis itself, did you have an experiment that was particularly interesting to you?

JFZ:

So the experiment is called tunnelling spectroscopy. It won the Nobel Prize for Brian Josephson, Ivar Giaever and [Leo Esaki]. So it was 1963 or so and it's actually a very simple experiment. In physics, there's something called quantum tunnelling where the transport of an electron through a barrier is possible without the electron actually burrowing through the barrier. Its wavefunction leaks into the other side, and so it can bounce off this barrier a million times and then actually pop out on the other side. This is something that is predicted in quantum mechanics and there were experiments that tested it and won the Nobel Prize. Two of them were with superconducting materials. One was in lead; That was Ivar Giaever's work. So it turned out that the experiment allowed you to measure a property of superconductors, which is the energy gap. In superconductors, the superfluid happens when the electrons pair up into something called a Cooper pair and that acts like a boson. Bosons can condense into a single quantum ground state and form a superfluid. Josephson showed that the pairs themselves could tunnel through the barrier. That was predicted; He predicted it. Most of the experts in the field said it wouldn't work and so he predicted this. Can you imagine being a graduate student predicting something, and somebody like John Bardeen who won two Nobel Prizes in Physics say that you're wrong? But he turned out to be right, Brian Josephson, so he won the Nobel Prize. So anyhow, this area of research was still very exciting and people were trying to use the technique on a material called niobium, which has the highest superconducting transition temperature of any element. So, we devised a method for doing it. The native oxide of niobium is just horrible for making tunnel junctions. The native oxide of a material is thin enough to have quantum tunnelling of electrons. So it's called a metal insulator metal sandwich. Imagine a film of lead. Let it grow an oxide, then put another film of lead on top. You make a sandwich of the metals and in between is a very thin oxide, which is insulating, and it's thin enough to have quantum tunnelling as the channel for electrons to go through it. That was very exciting. They wanted to do it with niobium, but its native oxide was not very good. So we tested an idea that we would coat the niobium with aluminum, a very thin layer, and let its oxide grow, which was an ideal tunnel barrier, and that method worked. So my PhD thesis was successful and I kind of joke around that I'm working in quantum hardware and it's the same problem. They make niobium as a thin film that's part of a superconducting qubit, and so its native oxide is bad. I suggested coating it with aluminum, because that's what I did for my PhD thesis back in 1980, and so that's what they're doing now. [capping layers] It's working, so the technique still is a good idea.

JHT:

You've brought up Bell Labs and now Dr. John Bardeen. Was the culture or influence of Bell Labs still present at this time?

JFZ:

Oh, for sure. They thought of themselves as the top research lab in the world and here was this kid from Ames, Iowa, doing an experiment which is what they should have done. So they were very critical. My very first experience giving my presentation, I was being asked dozens of questions and I just thought the audience was very interested in what I was doing. But they were trying to make me say something that was wrong. So they were highly competitive and the experience with Bell Labs was certainly there, but I would say it was not a good one.

JHT:

With quantum tunneling, we recently had the Nobel Prize relating to attosecond measurements announced. Has that, particularly with respect to either tunneling or your research generally, had any influence that you can recall?

JFZ:

For the attosecond optics?

JHT:

Yeah.

JFZ:

Had I stayed in optics, it probably would've been more important. In some ways, yes because what I'm doing now is helping design superconducting accelerator cavities and these accelerated electron bunches are being used to create an x-ray laser. These x-ray laser pulses are going to be at attosecond; You're going to be able to take a movie of chemical bond formation. So, it's related to the Nobel Prize, but not exactly the same thing, but it's the same idea. You do this with x-rays rather than visible light, but the idea is that if the pulse is sharp enough, you can take a movie of a physical process. In this case, what they're trying to do is take a movie of how a chemical bond is formed, so how do the electrons act in real time. That should be pretty exciting. It's a very exciting time for students right now, if you are interested in science and physics. There are lots of different opportunities out there to participate in a lot of exciting research. You obviously know about lasers. You use laser pointers and so forth, but you probably never thought that an x-ray beam could be a laser as well, and that machine is two miles long. Your laser pointer is only a few inches long, but to make an x-ray laser, you need two miles of accelerating cavities.

JHT:

What was the season of the Nobel Prize announcement like? Was it always an exciting time?

JFZ:

Yeah, sure. We would have discussions and a lot of the Nobel Prizes in the 1970s and '80s were in the area of particle physics, because those accelerators were producing new particles all the time. So the theoretical field of what we now know as the standard model was first being discovered. Those experiments were first being discovered, where you have three different families of elementary particles and so forth. So that was exciting; That was basically the heyday of particle physics because new particles were getting discovered it seemed like every month. So that was an exciting time, and our department had experts in nuclear physics, particle physics, optics, astrophysics, condensed matter physics, so it was a pretty exciting department.

JHT:

Did you ever predict a development that would win a Nobel Prize?

JFZ:

Well when high temperature superconductors were discovered in 1987, we were absolutely sure that it would win a Nobel Prize. Imagine superconductivity starting in 1911, and here it is in 1986, which is 75 years later and the highest transition temperature is about twenty degrees Kelvin, and now all of a sudden, it's much higher. There was a famous experimentalist, Bernd Matthias. If you interview Carlo Segre, that was his advisor back in University of California San Diego. He had what were called Matthias' rules and he said you never look in this area for superconductors, you don't look at oxides because they're all insulators or bad metals, and it turned out copper oxides had the highest transition temperature. Then he said you don't look at magnetic materials because magnetism and superconductivity don't get along, but now iron-based superconductors were discovered maybe twelve years ago or so, and that's an exciting area. So the two areas he said don't go into, people went into and made fantastic discoveries. So, for 75 years the highest transition temperature was about 20 K, and then somebody comes out with one that's 40 K, and then 60, then 80; Every week it kept going up. Then it was 95 K, and then in some cases, 120 K. So, 75 years you're stuck at 20, then a new class of materials comes in, you're close to 100 K. That was obvious that it was going to win a Nobel Prize, but we didn't know how quickly it would be. It was one year after the discovery that it won the Nobel Prize, so it was the shortest period of time after a discovery.

JHT:

During your time in superconductivity, have there been any major disagreements in the field?

JFZ:

With high temperature superconductors, people have still not agreed on what the mechanism is for pairing. In conventional superconductors, one electron excites the lattice, the lattice distorts – it's sort of like throwing ball bearings onto a flexible rubber drum membrane. If you put two of them, the first ball bearing carves a little slot and the other one sort of follows it along. That's basically what's going on with conventional superconductors. An electron is distorting the lattice, and that lattice distortion is attracting another electron. So that's the origin of Cooper pair formation. Now you have high temperature superconductors that are at 100 K, and the question is, is there a different mechanism? At the time, there were probably 25 different theories that were out there that were independent and so you knew that at least 24 of them were wrong. So it was just a matter of time before you could start knocking one or more out, and there still is no agreement, although I think that's just stubbornness. I think people know what the mechanism is, just not the exact details of it, but it's not phonons. It's something called spin fluctuations and it's sort of an exotic mechanism of superconductivity.

JHT:

Bringing up your advisor, Dr. Wolf, again, there are two questions that he said set the stage for the development of experiments in electron tunnelling spectroscopy in modern surface physics. The first is,"What are the key properties of metallic compounds that will lead to higher superconducting transition temperatures?" I want to ask whether you think this question has been adequately pursued and what role it's played in your research. 

JFZ:

So I would say the theory of conventional superconductivity is well understood, but starting from what's called first principles and actually calculating the superconducting transition temperature from scratch is still a challenge. You have to make approximations to do these simulations. So the theory is good but not perfect. There is no property that would have predicted high temperature superconductivity. It's just too exotic, too unusual, and it had to be discovered first. No one would have ever been able to predict it. Here, it's been discovered and you have all these experiments and people still fight about what exactly is going on, so try to imagine someone actually predicting it based on other properties of materials, and that is highly unlikely to happen.

JHT:

The second question was, "How can we predict and form materials with these properties?"

JFZ:

It's not easy. I know people are trying to use AI and machine learning, where computers just have the database of all the properties of materials, and they're going to use that database to try to figure out what the rules would be. I just am not confident that's going to work at the moment. It requires a deeper understanding of what's going on and a little bit of luck. The people who discovered high temperature superconductors had the wrong idea, but they went in that direction and discovered it, but what happened was not because of what they were looking for. It's serendipity. They were looking for one thing and they found something else which is serendipitous, so I think there's a little bit of luck, human ingenuity, just sort of saying I think this area might be a good idea to look, and I don't know if machine learning or AI would bring you in that direction. I think human intelligence is needed for this.

JHT:

You mention the use of machine learning. How has the development of computers and these types of computational methods influenced your field?

JFZ:

I think it's a great tool, because it can sort of give you information about why things might be happening, but it's not going to be exact. So right now, you can do what's called density functional theory to predict the superconductivity of niobium, and you will get close. You get the energy bands. Once you have the energy bands, you can distort the lattice and see how the electrons distort and build that into your computation. So if a material is 20 K and your computation predicts that it's 17 K, that's a pretty good result but still not perfect. As to predicting new classes of materials, I don't know. I don't have faith that it would lead to an entire new direction. Say, create this compound out of these atoms and you'll discover room temperature superconductivity. At the moment, I just don't see AI or computational models to be able to do that, because these models are approximate. They're not exact.

JHT:

So you’ve been quoted saying “Dr. Harold Manasevit’s discovery is now one of the leading technologies of the twenty first century and still growing. He should be as well known as all of IIT’s other innovators.”

JFZ:

Yes. I met Harold Manasevit many years ago before he passed away and I didn’t know who he was. After meeting him, he was just an alum who worked at some research lab and did some good things. So I shook hands and talked with him and we chatted, and then as I started to dig in to what it was that he did, he actually invented the method for making what are called 3-5 semiconductors in thin film form. The method is called Metal Organic — I don’t know if anyone here is in Chemistry — but it’s an organic compound that is a gas then you put a metal atom like gallium on one then you have another organic molecule and you have arsenic on it. Then you have the organic molecules touch a heated surface and they give up this metal atom to the surface and then the organic molecule goes away. So it deposits gallium and arsenic atom by atom on a surface, so it could form a layer of gallium arsenide better than you could make by other techniques. This technique, MOCVD, metal organic chemical vapor deposition, is the way that you make all of the LEDs that you see as flat panel displays, as LED lighting, so he invented something that has transformed our lives. We’re replacing all these inefficient lightbulbs with LED lights. It has allowed the flat panel displays, things like that. It’s allowed the formation of blue and UV lasers. So the energy savings alone from LED lighting is amazing, so the impact of what he did is something that I think he needs to be recognized for. I sort of imagine that we should have a center at IIT called the Manasevit Center for MOCVD Studies, something like that. So it is a pet cause of mine to give recognition to somebody who should be better known on campus than he is.

JHT:

I believe there’s another researcher whom I recall you saying is also under recognized, who predicted the Higgs Field.

JFZ:

Oh. Yeah, that’s Philip Anderson. He did win a Nobel Prize in Physics but I said he should’ve won a second Nobel Prize for the discovery of the Higgs particle, because he’s the one who came up with the idea. I think the idea is the important thing, the rest is mathematics. What did Copernicus do? He had an idea. He said the reason the planets have weird orbits is because our coordinate system is attached to the earth when really it should be attached to the sun. That’s the idea, and once you have that idea, transferring the planetary motion as if it were with reference to the sun makes all the difference. All of a sudden these weird orbits are now ellipses or circles and so it all makes sense. The idea though was to move the coordinate system from the earth to the sun, so Philip Anderson’s idea was to say let’s imagine that the vacuum of space is behaving like a superconductor, and if you just do that, you can solve three of the major problems that were outstanding at the time in particle physics. What was the nature of the phase transition? Well that’s the phase transition into the superconducting state, so that’s the symmetry breaking. It’s a way to generate fermions mass. So, the theories of the standard model, you have to start with massless particles, but then we know particles have mass, so how did that happen? Superconductivity tells you how to do that, to give the bosons and the fermions mass. So, it was just a conjecture. Let's just say space is acting like a superconductor. That would be a superfluid, so things would still flow through space but it would have properties that would give mass to particles. It's a scalar field, so the theory of superconductivity is a scalar field, which pairs the electrons, and that's the pairing potential. It's a complex scalar field which means it has two scalars, one that's imaginary –  it's an amplitude times e to the i phi, so that's the idea and the dynamical equations of the scalar field would be the equations that come out of superconductivity, and how do you prove that the scalar field exists? I always like to say there's a scalar field in this room, which is the density of air at any point in space, so how would you prove that that scalar field exists? Just clap. Everybody now hears a sound. The higgs boson is the equivalent of that sound wave that tells you that the scalar field exists. So, how the Higgs field gives mass to particles, you need a whiteboard and a little bit of math to show how that works, but it comes straight out the field of superconductivity. If you read the original Higgs paper, the third reference is to Philip Anderson's idea, and what Higgs did is take it to a relativistic field theory and all these predictions still held. So I just feel like the person who came up with the idea in the first place ought to get credit for it, but he didn't, but I guess they figured he had a Nobel Prize already, so why give him a second.

JHT:

We have a whiteboard if you'd like.

JFZ:

Oh no, that's okay.

JHT:

Well, that was a great explanation of the Higgs particle.

JFZ:

Yeah, the Higgs boson is the sound wave of the field, so you clap your hands but in the vacuum of space when you slam particles together. Then this excitation you detect. I think there's a misconception that the Higgs boson itself gives mass. It's not. It's the field that gives the mass. The boson is the fingerprint that the field is there, you've measured it, so it actually has kind of a simple explanation.

JHT:

Inspired by that great explanation, I'd like to discuss your role with education and how you've viewed it throughout your career, if you've generally had a passion for education even before your PhD.

JFZ:

I do, but probably in a negative way. I think when I finally got my answers to questions, I'd go back and I would think, you know if this was just explained a little bit better, it wouldn't have taken me two months to understand something, maybe an afternoon. So I've had those experiences where you don't understand something and then you talk to different people and somebody gives you an answer and then it becomes obvious. But also, I think experimenting is a way to get a feel for something. I think my passion is that theoretical physics has increasingly become divorced from experiment. There are just ideas out there, mathematical constructs. So the field exists just because it looks interesting, but it's not testable for whatever reason, and I think that those are dangerous areas to get into because you could be spending your whole life learning a theoretical field that has nothing to do with reality. I think I'm in favor of theoretical models and so forth that can make predictions that you can test with experiment. I think that would be my prejudice. I think just theory by itself that's decoupled from experiment is a dangerous field, and in the field of particle physics, there's a thing called supersymmetry, which was taught for so many years that everyone sort of thought that it was correct. It made predictions about particles that should have been discovered with the large hadron collider, but were not. So now what do you do? You've spent 30 years of your life doing theory and now it looks like the predictions of this theory, those particles, have not been found. But at least that theory was testable – you make predictions about masses of particles and at the very least it was testable, but it's an example of theory by itself which seems like it should be right because it's beautiful and mathematically structured in such a way that it appears beautiful, that if it's not tied to an experiment, that it's kind of a dangerous thing to get into.

JHT:

How have those beliefs played a part in your teaching of physics classes and the advanced lab, perhaps in the context of IIT being founded as an educational institution for engineers?

JFZ:

Well the advanced lab is only for physics majors, not for engineers or computer science majors, unless you wanted to. You could always take it as an elective. I think having an engineering school is good, because they are taking fundamental discoveries in science and turning them into useful devices. I think that's a good thing. I think the students enjoy that. I think it's great to have a science department and engineering college on the same campus; I think it's good for everyone.

JHT:

So you authored a textbook, I believe on the history and applications of Josephson junctions. What was the inspiration for that?

JFZ:

Well, when I was talking to my former advisor, Ed Wolf, I said that we didn't get enough credit for this aluminum capping layer back in the 1980s and now you have all these superconducting circuits based on Josephson effects. The junctions are made with this capping layer approach, and now superconducting qubits are using the Josephson technology, that we should write a textbook that has the history part of it. The big deal was that you could make devices out of niobium. Niobium is what's called a refractory metal, which means it's very hard. It has a very high melting point. It's surface does not get damaged easily by chemicals easily or anything like that, so it's a very strong material and you want to make devices out of it. So, way back when in the late 1970s, we showed how you can make a tunnel junction out of it. That was a big deal. You've got an entire field called superconducting electronics and now superconducting qubits, which takes advantage of that method. We should get a bunch of authors to put together a textbook which talks about where the whole field has gone from those early days, and so that was the inspiration for the book. It's basically kind of setting the historical record, but at the same time, demonstrating just how useful these – a lot of people are probably not even aware that there's superconducting electronics being used for detectors and things like that. They're aware of semiconductor devices, but not superconducting devices, so this was an opportunity just to make people aware how of far this field has gone.

JHT:

Just before we began, you started discussing the relation between solid state and condensed matter physics. Might we go back into that?

JFZ:

I think the word solid state, in history, comes from things like amplifiers and high power RF generators that were made from vacuum tubes. Do you guys even know what a vacuum tube is? Have you seen a vacuum tube? You've never seen a vacuum tube? Okay, see we should have some display items. You can buy an audio amplifier with all the vacuum tubes. They sound better than the solid state amplifiers, but a bulky vacuum tube was being used as an amplifier and a rectifier, and things like that. So, electronic devices were bulky, huge boxes. So when they finally came up with the transistor, which was not a vacuum tube but rather a solid state silicon or germanium diode or transistor. Then they used the world solid state as opposed to electrons in a vacuum tube. Then the discovery of the transistor transformed the economy of the United States. All of a sudden, people realized that you can make a device which changed the economy of an entire country. So the word solid state physics became an important word to describe people working with things like semiconductors and superconductors, and optics, optoelectronics, things like that, which would be devices made out of solid materials. But then, people started to look at soft materials and liquids and that was still a condensed phase of matter, but it wasn't a solid, so people thought that the better way to describe the field and where it was going was to use condensed matter physics. That's a broader category which includes a lot of phenomena that you might call soft physics. Do we still have liquid crystal displays? Probably not. There still might be some numerical displays that use liquid crystals. Those were examples of interesting phenomena that would be called condensed matter that's not a solid.

JHT:

While this was happening, where was quantum computing in the picture?

JFZ:

Well, I think quantum computing, Richard Feynman, the famous physicist recommended that if you want to understand quantum phenomena, you need a computational element that had quantum mechanics built into it, because you cannot easily program quantum mechanics into a silicon based processor. It takes too much memory and too long of time. The other idea is that you actually have a circuit that would be what's called an emulator, that these circuit elements would be behaving like atoms or molecules that are interacting to form a chemical bond or something like that, so rather than being a calculator, it would actually be an emulator. You could tune the couplings and so forth and if you had a hundred elements, it would be like a hundred atoms interacting, and you could find the ground state for example. So that idea was out there I believe at least 25 years ago, and people started building them, but it's only been more recently, say within the last ten or twelve years that it's taken off, where you've got enough qubits in a circuit to do meaningful calculations. There's something called a coherence time of your qubit. How long does the dynamical motion of your quantum system last before it gives up its quantum of energy to the environment. A lot of the early qubit devices lasted only one microsecond or something like that, and then it got up to a hundred microseconds and then that become a threshold where one could start to see the creation of a real quantum computer. That's when IBM got into the game and then Google got into the game, and when that happened, that's when you knew that the field was taking off. So I would say it's been roughly about ten to twelve years where the field has started taking off. Now, it's really taking off. You've got companies and governments around the world – the European Union, I believe, is committing fifteen billion and China is committing fifteen billion, the US has already committed a few billion. Corporate investment is now four billion dollars. So that's serious money being put into something that they think will transform the way we solve certain physics problems and the way we handle data, things like that. I have to admit, I don't know enough about how you would use quantum computing to analyze the stock market, but apparently there are companies that are now investing in quantum computing just for that purpose. So like I said, we're part of what's being called the second quantum revolution. The first revolution was when we just understood how to explain phenomena using quantum mechanics, and now we're using exotic properties of simple quantum systems to make a computer out of it, and I think that, again for the young people in the audience, you're part of a lot of new trends that are just taking off and these are really great opportunities to be looking at. You want to get into something that is just starting to take off so you can get into the field early and maybe have your good twenty, thirty, forty year run. Whereas there are some areas of science that have kind of saturated, they are mature fields, it's hard to see something super exciting coming out of those fields, and I don't know if I want to mention any names because I might offend some people, but I think that at least the second quantum revolution, as it's being called, is very exciting at the moment. 

JHT:

We we had Dr. Marissa Giustina here recently, she ended her talk with the point that quantum computing is the pinnacle of research topics for fundamental physics. Would you agree?

JFZ:

Is that what she said?

JHT:

I believe that was close to her last slide.

JFZ:

I think there's just a lot that's unknown about the field, but what I'm confident about is that any time you're dealing with quantum phenomena, something surprising is going to come out. So even though we don't know exactly what a quantum computer will look like in ten years, there will be surprises, but I'm pretty confident that something exciting and useful will come out, although we can't predict at the moment what that will be. But whether she calls it the pinnacle of physics at the moment –

JHT:

Well, that wasn't the exact word.

JFZ:

Yeah, I think it's something that my gut instinct says that something good – well something exciting – is going to happen in the next five to ten years?

JHT:

Are there any field you'd say that are similar?

JFZ:

I guess I don't know enough about AI but that certainly seems to be something quite similar and Google is working on an AI robot, which I think could just be awesome to have in your house – sitting at the dinner table, talking to an AI robot. I think that would be pretty funny, to have dinner with your family and then there's the AI robot there that's part of the family.  So I don't know where it's headed. There's already a lot of disinformation out there and the last thing we need is AI generated disinformation, so that would be a bad direction, but that seems like an exciting area.

JHT:

During the past ten or twelve years you said of the developmental phase of quantum computing, where were you?

JFZ:

Where did I start? Okay, so we were doing experiments again with niobium and what the problems were of niobium oxide, and we found that the oxide was magnetic. It had magnetic moments; We could see it in our experiments that the oxide itself had these paramagnetic moments, which were surprising. Then there was another guy, Robert McDermott, at the University of Wisconsin was looking at these so-called flux qubits, quantum bits, and they were made out of niobium, and he was finding that there was magnetism on the surface of these, squid loops is what they're called, and so I said well oh we're measuring magnetism, this might be the same thing that you are seeing in your qubits. So I sent him an email and invited him to IIT and he came and gave the very first talk on quantum computing at IIT. I believe that was about twelve years ago and we talked about this common measurement that we had. That's when I got interested and there was an IIT student at the time working for me who then got accepted into McDermott's group and he's now working at IBM on their Q System quantum computer. So I've sort of followed the field through his group and then through him, working at IBM, and I saw the field explode. I'm at the annual meeting of the American Physical Society for condensed matter that we call the March Meeting. There was one session in an afternoon, and then the next year there was an afternoon and a morning session, but then there were a couple of them, but then in the next year the entire week had sessions both morning and afternoon every day of the week. So you just saw this field exploding and he got a really great job out of graduate school working at IBM. Normally after a PhD, you take a post-doc, maybe a second post-doc, and then you get your permanent position, but IBM just scooped him out of University of Wisconsin and paid him a lot of money to go work on their quantum computer. We had a similar experience at IIT where we had a theorist – Pedro Rivero was using quantum computing to do a problem in theoretical particle physics called a Nambu–Jona-Lasinio model, but he was using quantum computing to try to analyze it, and he got hired by IBM. They offered him a job eight months before he graduated I believe, with his PhD, so as soon as he was done, he had a job at IBM, so there's two examples of former IIT students who got into the field, one in theory, one in experiment, and are now working at IBM.

JHT:

What was the first student's name?

JFZ:

Matthew Beck. So he would always give me the inside information – well not totally inside, because a lot of it is privileged information, but I got to understand that the field was really taking off. So, at IIT, I suggested a number of years ago to the provost at the time that we have to start looking into this field for our university. I said sooner or later that there are going to be two universities, ones that offer courses in quantum computing and ones that don't, and so we don't want to be on the other side. So that's where we hired Rakshya [Khatiwada]; We got a half position, and we're still trying to develop this initiative. We think we need a theorist to teach graduate level quantum computing. That would be someone that we would like to have. So that's another goal.

JHT:

With the research happening in the Department of Physics – you mention Dr. Khatiwada – if I recall there was a relativity group very early on, I think in the '80s. I'm just curious how the landscape of research has developed in the department.

JFZ:

So when I arrived in 1982, there was a group of three theorists working on the Einstein field equations, but that was discovered in 1915, so by 1982 that's 67 years of people looking at these field equations, so that was an example of a mature field that really was not going to make many advancements. I know LIGO is detecting these binary neutron stars that are generating gravitational waves and merging, but the theory behind that was developed, I believe in the 1970s. So that group moved on and it was replaced with our condensed matter group, and so that was a successful transition. I think the question you're asking is how might quantum computing be used to answer questions in astrophysics, like what is dark matter? So this qubit is extremely sensitive and if you have a qubit sitting inside of a cavity, then there's examples where dark matter, and we don't know exactly what it is, but some particles that are considered dark matter can turn into a photon, just a single photon, inside of the cavity and if they did, a single qubit would be able to detect this single microwave photon that was created, because it would bounce around the cavity and finally get detected. So that's the idea that you could use a qubit as a very sensitive detector of photons which would then be useful for fundamental astrophysics questions like dark matter. Now they're thinking of using them to detect gravitational waves as well, but I have to say I don't know enough about that to explain, but you have a very sensitive device and you use the sensitivity of this device to create very sensitive instruments to look for fundamental particles. We still don't understand what dark matter is and so having these super sensitive devices might be a way of helping us find them.

JHT:

Has the Department been close with other departments? I know it's changed and merged.

JFZ:

Physics? I think it depends on the individual faculty member. In the materials science department, there was Sammy Tin, and we didn't do research together but we talked a lot and I was on the committee for his graduate students and he was on the committee for my graduate students. Phil Nash was another person. So, I think it depends on the individual faculty member and who he or she interacts with in Engineering. So I don't know if the department as a whole – it's on an individual basis.

JHT:

During the time of the department being the biological, chemistry, and physics department, what were the motivations for that and how did it finally get catalyzed out of that?

JFZ:

I think the motivations at the time really, to be honest, it was a cost cutting move, because by merging smaller departments into a larger department, you could save on administration. The problem was that it was an experimental idea and not a lot of other universities had combined science departments, so it was a little bit of an odd situation. It was also a difficult department to manage because the needs of biology faculty, chemistry faculty, and physics faculty are different. So it's not easy to manage the three different cultures. So I did that for five years [as Chair] and when I was done, I recommended to the dean that we split the divisions back up into their own departments and so that's what happened. We now have a biology department, and chemistry department, and a physics department.

JHT:

So how long after your recommendation did it take?

JFZ:

I think it was about a year or two because one had to have a plan. Then you needed department chairs and things like that, so it took a while.

JHT:

It's approaching 2:45. It's 2:35 now.

JFZ:

So 2:45 is going to be our?

JHT:

It was the scheduled end.

JFZ:

Any questions from the audience?

*inaudible*

JHT:

Thank you for your time.

JFZ:

Thank you.