(electronic music) - Welcome to a Conversation with History. I'm Harry Kreisler of the Institute of International Studies. Our guest today is Steven Chu, who is a Nobel Laureate in physics and Geballe Professor
of Physics at Stanford. He is the 2004 Hitchcock
Lecturer on the Berkeley Campus. Steven, welcome to Conversations. - Thank you. - Where were you born and raised? - I was born in St.
Louis, not raised there. I only spent a few years there. My parents then moved to Long Island. So I was raised in a
suburb of New York City, Garden City. - And looking back, how
do you think your parents shaped your thinking about
the world and about science? - Oh, that's a tough call. (Harry laughs) Because most of how all
parents shape people is very under-the-table. You're not really aware of it. I was aware of many things, though. My parents came from China. They came here as graduate
students to go to MIT, and, like many Chinese
in higher education, there was sort of a
reverence for education and that they communicated
very clearly to me and my two other brothers,
that one of the highest things you could aspire to is to be a scholar, and to be a scholar just
for the scholarship's sake, not so much as a stepping
stone into some other job, and that was communicated very well. And while we were young,
they would always say read. They didn't care that much what we read as long as we read, and there again was something that I felt. - And you didn't
necessarily take to school like a fish to water. I read a short biography
that is at the Nobel website. I mean, you got interested
and were a good student when you got interested, I guess
is the way to summarize it. - Well, you have normalize
this to what was happening. I had an older brother who
was an excellent student. He was two years older than me. We were in a school, Garden City, and it was a very good public school, excellent public school, and he went through this public school setting the highest cumulative average in the record of the school. - I see. - And so I follow along two years later, and the teachers would say,
oh, you're Gilbert's brother. We expect you to do just as well. (Harry laughs) And so that was hard to really live up to. So while he was setting records, I was kinda coming from behind. I was an A minus student. By my family's standards,
this was appalling. (laughs) He was very good. He was very structured and
he would study the things he was supposed to study, and he was fundamentally
a very good student, and I would get very
interested in one thing and let something else lay,
and something like that, and it wasn't really
until I went to college where they didn't hear my older brother. (both laugh) - But in high school, you
were turned on to science. How did that come about? - Well, there were two things. One is I had a fantastic
physics teacher as a junior. - [Harry] In high school? - In high school. And then the same teacher
as a senior in high school, and this is someone who
is nationally recognized. He was winning prizes for being an outstanding science teacher. - [Harry] And his name was? - Thomas Miner. I had two excellent mathematics teachers, one in ninth grade in geometry and then a calculus
teacher in the 12th grade, and there the mathematics was different than the other math. In the other type of mathematics, you learn how to do
algebra and trigonometry and things like that. In those two subjects, it was mostly about logic and thinking and putting together logical arguments, and it was very different. And the physics and the logic
slash mathematics courses I got very excited about. - And you also early on
were something of a person who liked to build
things and do experiments and litter your mother's
living room with projects. Tell us a little about that, and then how that ultimately contributes to what you become. - Well, I don't know what it was, but since I was very young,
I loved building things. I loved building things with my hands. I would be given a
model set for Christmas, model airplanes or boats and things. I loved to put them together. I would ask my parents for
things like erector sets. These are little pieces
of metal and screws and unlike Lego blocks, you actually have to
screw something together and it wasn't all pre-designed to make a boat or something like that. And I loved doing those things. In that respect, it was somewhat different than my two brothers. In many respects, my brothers
and I are very similar, but in that respect, I seemed
to love mechanical things in a way that was certainly
nurtured by my parents in that they said, okay, he
wants to do these things. We'll buy toys like that for him. But my other two brothers
didn't seem to like that. Now it turns out that
working with your hands and building things gives you
some sort of spatial intuition and things like that that
turned out being valuable once I became a scientist. I could see things in my head very clearly and could rotate them around and this idea of picturing
things geometrically has always been a part of my thinking even though one doesn't think of that, at least the lay person
doesn't think of that in terms of physicists. They think in terms of
mathematical equations. And I only discovered later
that most physicists do that. - Now then you went on to collge and you were freed of your
brother (laughs) so to speak, as a model to emulate. Where did you do your undergraduate work? - I went to the University of Rochester. I applied to the Ivys. They didn't accept me. And University of Rochester was wonderful because it's an excellent school. It was then, and as I said,
my brother was an unknown. I could be my own person. And I guess I started working very hard in a regular way still,
but in a very directed way. But what's wonderful about college is beyond a few required courses, you can take what you are interested in. And then there was another
thing that happened in college that I wasn't really
thinking of, and that is, as I studied more mathematics, it actually affected my writing. My writing became more
linear in its thinking and you could definitely see
some logic in the writing that I didn't have when I was
in high school, grade school. So my humanist courses, the
professors there were being, hey, this is a coherent paragraph, and I wasn't really thinking about that, but it was almost as a magical transition from the mathematics I was studying. - Drawing on that right now, why is it that the public understanding of science doesn't
proceed at a higher pace? Is it because not enough scientists are doing the writing? - That's a difficult question. As I give more public talks, as I get exposed to these
issues more and more, I think that there are two things. One is unfortunately there
is a public fear of science. They think, especially physics,
they think, oh my gosh, physics is hard. It has math in it. It's gonna be very difficult
for me to understand what's really going on. That, I think, is something
that might've happened in grade school or high school. (both laugh) - [Harry] They didn't have
the right teacher, right? - Yes, and the trouble with
learning physical science and mathematics is once you
slip behind a little bit, and you just didn't get this concept, or it's not quite firm in your mind about this mathematical
thing that you have to know, well, then next week you're
on to something else, but they really expect you to know something about last week. So that's one of the issues. The other issue is that
the ideas are complex. But if you step back and if
you spend some serious time thinking about it, the kernel of the ideas are quite often not complex. And so the essence of an idea,
which we try to work with-- As a professor with my graduate students, we would read a paper, and
look at the paper and say, well, what's the essence of the idea? What's something new? Forget about the equations. Forget about the complicated arguments and try to identify the kernel of the idea and I think that can be communicated, but it takes effort. - Now you did your graduate
work here at Berkeley, so in a way, you're coming back to deliver the Hitchcock Lectures. What contribution did your
Berkeley education make overall? I'm sure you could go through a long list, and who was your mentor here? - Well, my mentor was Eugene Commins. He was a wonderful professor. He has a history of having
many graduate students that have gone on and
done wonderful things, and he's revered as a
classroom teacher as well. And also in the way he does things, the way he goes about life. So in every respect that I can think of, he was a mentor, not only
in terms of the science, but how you handle yourself
in terms of situations and how you handle yourself in the world. Now he had one remarkable
quality that I wish I could copy and that is he made all of
his students feel special, and they felt that they were special. They could do something
and he really got all of us to live up to the highest we could do without saying you must do this or without making us
feel pressured or guilty or something like that, and he would work side by side with us, often late into the night, as a colleague more than as a professor. So that was a remarkable experience, to grow up in that environment. The other thing I learned here is to try to think of things to do that would be important in science. There are many things
you can study in science, but focus on some big questions. Try to identify the correct questions and there it was not only my advisor, but the Berkeley professors
around here at that time, there were six or seven Nobel Laureates in the physics department active, and you can watch the way
they approach problems. And this would come out not in a formal lecture or something, but in casual conversation, when they're maybe giving a colloquium, how they approached it,
how they thought about it, and this also enters in
a very subconscious way. That is probably why there are so many distinguished
graduates of Berkeley as well. - Now help us understand
what the prerequisites are for doing science well. If a student or students
were to watch this, what should they know
about this way of life and what they need to bring
to it in training and so on? - Well, I think the first thing is they have to be interested in it. They have to be genuinely interested. They have to have some curiosity. Science is really about describing the way the universe works in
one aspect or another, all branches of science. How a life form works, how
this works, how that works. And so you're really trying to
understand what's around you and you have to have a
natural curiosity for that. In certain types of science, there might be some prerequisites. In physics, you should have
some mathematical ability. Otherwise, I think it would be very hard. But beyond those prerequisites
that a lot of people do have, you need to have first this curiosity, but a really driven curiosity. You want to know the answer. And with that curiosity comes
with it a certain doggedness because there are gonna be setbacks. You're gonna discouraged. Things aren't gonna work. You're gonna have trouble
understand things. Things are gonna be hard to understand, especially the first time. Science doesn't come naturally to people. I had the hardest time
in my first few years as a freshman and sophomore
understanding physics in a really deep sense,
and also in high school, in the sense of, I could
do well on the exams, but to really get it inside your stomach and to really say, okay,
I have a real feel for it took awhile to develop that intuition. But there were other drivers for that. It seemed like a beautiful way
of understanding the world. But I'll go back to the
other thing, this doggedness, this real saying I'm not gonna quit. I really wanna find out. It enters in other walks of life. If you think of an athlete who wants to become a good athlete, well, there's gonna be a
lot of training involved and sometimes you don't
feel like getting up early in the morning or
staying late in the afternoon and spending hours training. And so that turns out to be one
of the most important things that separate in graduate school. At graduate school at Stanford, you have some of the best
students in the world, and the ones who you
can see are gonna go on and become world-class scientists, and the ones who are very
smart and are gonna be good, but the thing that really differentiates is this passion to find
out what the answer is and I'm not gonna quit. And so after those prerequisites, the thing that separates the people who are really gonna excel from people who are good and not is that, this internal drive. - In a joking aside
yesterday in your lecture, you said that in science,
once you announce something, that first everybody
tells you you're wrong. Then they tell you it's trivial, and that you were not
the first to discover it. Well, it really emphasized
what you just said, that there has to be an inner drive, but also it suggests
an element of courage, that basically you're
gonna stand up to people and say, no, this is what I think, and then keep on going
even if you're proven wrong and then try to adjust what
your experiment has shown. - Yeah, that's right. And when you make
something that's unexpected and it's a little bit out
of people's expectations, they're first gonna reject it. And actually, that's one of
the strengths of science. You really have to say, no,
it's not because I said it is, but you're gonna have to convince them, and by convincing them, it's
really through discussion and additional experiments, because in the end, the
experiment is gonna be the final arbitrator. There's no high priest
or priestess of science that says, no, you're right, you're wrong. You go back and you do
some more experiments. So the reaction, if you're
a little bit off center, or a lot off center, is
no, that's preposterous. You've gotta be wrong. And the more outlandish you are, the more unexpected the finding, the more you're gonna get that reaction. Now in the end, after one really
understands what's going on, and it goes back to really
understanding the science, then you say no, no, no, it's all right. Yes, we could've foreseen that, and that's where it becomes trivial is the, well, sure. But it wasn't trivial at the beginning, but after you see it,
then it becomes easy. (Harry laughs) But that's actually a mark of really understanding something. Then they say of course. And then the final one is you're not the first to discover this. That is also true. (laughs) There are always precursors. (both laugh) And there's always someone before you, had a glimmer of this
and a glimmer of that, and science is based upon
a lot of rediscovery. But going back to your point, namely you're gonna be rebuffed,
and oftentimes rejected, and it's not a personal issue, and you just gotta stand
up to it and go back. Now you could be wrong, but you're gonna go back and convince yourself you were right. The rule I tell myself and my students is once we convince ourselves, we have to be our worst critics. And once we convince
ourselves that we're right, then we should have no problem convincing everybody else we're right. And so a good scientist
is their worst critic. They're always trying to
prove themselves wrong, which is hard, because
sometimes you've got and idea and you think you're really right, and you have to force yourself. Well, where are the weak
points of this argument or the weak points in my experiment? - One of the points that came
out in your lecture for me, a non-scientist, was really the
importance of collaboration, not only with your own students, but with other scientists,
and even other scientists who are in subgroups within physics, but even beyond that to scientists in other fields of science, that those sets of
communications working together are really important to
push this process along. - Yes, that's another misconception that many people will
have about scientists, or doing science and learning science. This misconception is you go to school, you take classes, you study. Years and years of study. You learn everything there is
to know in a certain subfield, a very narrow certain subfield, and then you do work in that area. And that is a form, but it's rarely taken, and it's especially not
true for the way I do it. Maybe it goes back to my high school days when I was not such a good student, but in actual fact, if one
wants to go into a new area beyond your school days,
you can do the same. You can pick up a classic
textbook or something like that and begin to read the literature,
but it's not as much fun. And when I was going into
biology maybe a dozen years ago, I did try that. I picked up this big fat
tome called Biochemistry, a classic textbook, and
I started reading it. It was, I don't know, 1,500 pages. I got to page 150 and I was deciding, well, it's beginning
to slip out of my head as fast as it's going in now. (laughs) I reached some steady state, and so I said, well,
this isn't gonna work. So I would look around, and I had something for
reading newspaper science, Science Times in the New York Times or Scientific American,
things of that nature. So I had some interest in
these biological problems and I would pick something
that I was interested in. But, of course, since I
wasn't an expert in biology, I didn't know, is this a stupid question? Is this a deep question? So I'd say, well, I think
I can do something here. I have some interest. So I'd go over and trot over
to the biology department or the medical school, say is
this something worth studying? I think I wanna do this. And they would tell me,
sometimes no, no, it's silly or it's been done before, or sometimes they'd say no,
no, this is the central problem in biology. (both laugh) That rarely happens. But what happens is then I
would start to collaborate with these people who spent
their career in this specialty, and their students also, and
they grew up in this culture, and they would say, you
should read this article and that article and that article, and we would talk, and it was
wonderful to learn that way. So you can leap frog
over the years of school. Now, to be sure, I'm not pretending I have as broad or as deep knowledge of that, but then you start with
a little thin sliver of a particular problem
and you start to build knowledge around that thin sliver, and by the time you've done the experiment and you're starting to write the paper, you better have some
knowledge of what's around because you won't even get
to publishing the paper because you wouldn't have
referenced the right people of the precursors before you. But it's learning in that way, and then you go back to the books, but now you use the index, and you say, I wanna learn about this. So now I've begun to teach my students. Many of my students are
physicists wanting to go into biology, and I say,
okay, we'll use the index. This is the kind of problem. Why don't you look here? Read these five pages in this book and these 10 pages here
and these 15 pages here. By that time, you read
this review article, and within a month, you're
reading the primary literature. - In biology? - In biology, right, without
the three years of courses. And then within a few
months to a few years, then you're beginning
to get a feel for it. It's very important that you get this feel because you have to ask
the right questions. One of the most important
things that a scientist does is ask a question that's important and that has a chance of being solved. You can ask important questions, like how does the brain work? But that's not sufficient. You have to pick a part of that question to where you can make a contribution, but a serious contribution, and something that others
would be interested in. - Before we talk about
some of your research in a way that I can understand,
and maybe the public, too, in your career, there was
a period when you went to the Bell Labs, and I
wanna understand how that contributes to your research, and understand exactly
what the difference is between being in a place like Bell Labs versus being in the physics department at Berkeley or Stanford. - Right, well, the reason
I went to Bell Labs, I was actually here as a
graduate student at Berkeley and I was a postdoctoral fellow here, and after two years of that, they actually made me a faculty member in the physics department, but this was a bit unusual because I had spent
eight years at Berkeley, and I was essentially toilet trained here, and I had a very narrow vision of science, and what a department
really wants is to bring in people from different sorts of cultures. But they decided they
wanted me as a professor. It was a beautiful place, so I accepted. But then they did something very unusual. They said, well, you can start your group and go about your business, or, because you've
spent so much time here, and this was your only real experience, you also have an opportunity
to go somewhere else for a year or two. And so I thought, well, that's wonderful. I have a job at the
best physics department in the world here, and so I'll go off and spend some time and broaden myself. And so I decided to go to
Bell Telephone Laboratories, which, at the time, was one of the premier
research industrial labs. When most people think of industrial labs, they think of, oh, you're
making some better widget. You're making something
that's gonna be good for the phone system. Now ultimately that's true, but at Bell Labs in that
time, and this is 1978, they allowed a small
fraction of us, 50, 60, 80, to do whatever we wanted,
really to do whatever we wanted, and so I joined Bell Laboratories, and my department head said, well, Steve, you can do whatever you want. It doesn't even have to be physics. All we ask is that you don't go to a high energy accelerator
and do high energy physics because that would be
hard on the stockholders. (both laugh) And because my thesis project and what I worked on as a
postdoc did have something to do with high energy physics, Not something to do, it was addressing a high
energy physics problem, and he said, and by the way,
don't do anything immediately. Spend six months, talk to
the people around the labs, and just keep an open mind. This was a devastating experience for me (both laugh) because the freedom to
do whatever you want and being told don't do what
you think you want to do now, but explore. And so I'd spend some time exploring, and there I really felt pressure because he would say, we
expect great things out of you. And I don't wanna hear that. (laughs) It's much nicer to have a little problem and you're working on it. It's very cozy. But it did have a real influence on me because it got me in that mode of going and talking to
people outside of my field and when I finally started doing things at Bell Laboratories, I
started first in some area that was in condensed matter physics that I knew nothing about, but using techniques in my
own field, atomic physics and laser physics. But it got me into the mode
of, I've got this crazy idea, and going to some colleague
at Bell Laboratories and saying, well, how does this sound? And they would tell me, no, this is the stupidest thing I've heard, or yeah, maybe you have something there. And it really set the tone for what I've done for
the rest of my life, and collaborating with people, especially outside my local expertise. And so it was a wonderful experience. I also should say in the
years I was there, '78 to '87, there was an economic
slump in the mid-'70s. Bell Labs just started hiring people and there were a group
of us, maybe a few dozen, two or three dozen, and we
all were young, energetic, bright-eyed, bushy-tailed. We were all being put in this position. Do something important. Here are the resources of American Telephone
and Telegraph System. We expect you to do something wonderful. We were there at night. We were there in the weekends. We knew each other, what
our cars looked like. We knew who was in there, let's say, on a Saturday or Sunday. We would party together and
it was usually the salad days, and I think something on the
order of five or six of us got Nobel Prizes. Over a dozen are in the
National Academy of Sciences. It's like we all were growing up together and then we had these really
wonderful senior scientists there as well, and it was a
remarkable period of time, when everything was exciting
and something would come along that was not in my field, and I would say, wow, this
is really interesting. We'd go and we'd discuss it, and then people would
jump fields or jump areas, and there was this
feeling of the excitement of the science and even though we were doing this, it was all right to move and do that, and you wouldn't be considered a failure because you gave up this
because something else even more exiciting came along, either from your own laboratory
or from a colleague's lab or from the outside world. - So freedom in the best sense, but in an environment where
it could lead to new levels of understanding. - Yeah, it was a positively
electric atmosphere. You'd go in the lunchrooms and over lunch, everybody went there around noontime. You'd sit there in these big round tables and, okay, what's new? And people would leave,
other people would come, but you'd be sitting there
chatting, socializing, but talking a lot about science and a lot of ideas were invented
on those lunchroom tables. So there again, it was something where there was this real community. It was pretty magical
and I think the world, people who are close to science, especially in the areas
that Bell Labs was touching, knew that there was
something magical going on in that time. - And how can we
distinguish that experience from, say, being at Berkeley
in the physics department or being at Stanford? Was it just a question of
there were enough resources to bring all these people together to create this magical moment? - No, there was some other things. For example, in a university
like Berkeley or Stanford, you're a professor, you have students. And because you have graduate students, first you have students
as undergraduate students, and part of your job is
to teach undergraduates, part of your job is to
teach graduate students, you teach graduate students by giving them and developing with
them their own projects. And so a lot of energy and time
is spent nurturing students and because of that, your first duty is to
look towards your group. Well, at Bell Laboratories,
we didn't have groups. The biggest you could
have would be a technician and a postdoc, and usually not both. And so if you wanted to
something that required more than one or two people, you would have to work with other people. And so that builds into the system let's collaborate, and because no one had an
empire, or even a mini-empire, that in the basic science areas at Bell, you're one and two or three, you have a lot of time. You're not taking care of people. You have a technician or a postdoc. So it's a very different structure. We are trying to do something
like that at Stanford, in which we, in a multidisciplinary
way, are bringing people interested in biology,
physics, and chemistry, computer science, center
around biological problems, but where people from very
many disciplines will come and have their own agendas of what to do. One of the things is to
limit the size of the groups. You could have, in a university, let's say you're doing synthetic chemists, you could have groups of 40,
and with a group of 40 people, you're not gonna have much time
to interact with colleagues and you're not gonna have much
time to explore elsewhere. And so it's limited the
size of the group to 15, which is still very large. You couldn't limit it to three, because there are very few professors who have two or three graduate students in something related to
the biological sciences. They're typically more. And so the structure's slightly different and so it's not clear how much
you can create the structure we had at the laboratories because you have these other
responsibilities and duties. - Before we talk about this new link that you're working on
between physics and biology, let's talk a little about your research that led to the Nobel Prize, and if you could briefly give us a sense of how you came upon that problem set and what you in fact did. It's clearly related to atoms,
lasers, cooling, and so on. - Well, I was at Bell Laboratories. There are two main branches
at Bell Laboratories. The main research branch was
in Murray Hill, New Jersey, and I think it was in 1983, a director in Holmdel asked if I would become a department head in his division in Holmdel. The director, by the
way, is Charles Shank, who's the director of LBL, and he said, well, Steve,
why don't you consider coming down and starting a department that would be really a basic
science department here. Holmdel had excellent
science and laser engineering and a lot of the great
things that have come out of optical communication
were spawned at Bell Labs, in large part in Holmdel and Murray Hill. So I said, that sounds like a great job. I went down and started this department and started hiring some people, and also inherited some
very talented people. Actually, two of them are here also, Daniel Chemla, for a brief
moment, was in my department. He's now a division leader at LBL, and Geoff Voelker, who's a professor in electrical engineering,
was also in this department. And there was another really
wonderful scientist there named Arthur Ashkin, an
older department head, and I started talking to him casually, kind of in the hallways,
and he had this dream, wouldn't it be nice if you could hold onto an atom with light? And he had tried to pursue this dream in the early '70s and mid-'70s, but it wasn't really working. They did some very key
experiments demonstrating the fundamental forces, but it wasn't looking like
they were getting closer to really holding onto atoms with light. And so finally, the manager
said, well, it doesn't look like it's gonna come and you
gotta move onto other things, and he said all right. But then I came on board and
I was this new young person who he could corrupt (both laugh) with his dream. - You go do this, yeah. - And I started thinking, okay, this sounds pretty interesting, and started having a look at it, and I started doing a lot of calculations. It was getting to be bad. I was thinking, I can see why you quit. (both laugh) I was thinking it. I didn't tell him that, but
I was thinking to myself, no, it's not looking good. (both laugh) There's a few eureka moments
you can have in science. Mostly they're gradual eurekas, which I can come back to later, but there was this time and it
was not looking good at all. I would try it this way, that way. It's all on paper, not looking good, and finally, there was a
big snowstorm in New Jersey. They said over the PA system,
the forecast looks very bad. There's going to be nine
inches or something. The lab is going to be closed. You should all go home. Now I live very, very close to the lab so I said oh heck, and everybody left, and it was very quiet, and it's one of those beautiful things where you could see the snow falling down and everything's turning fluffy white. And maybe it's appropriate
because it's snowing, and then I found you can do an end run. The thing there was first
you hold onto an atom, then you get it cold, and then you can really
do what you want with it. And then I said, well,
what if you reversed it? What if you cooled down the atom first? Don't hold onto it, but
maybe in the process of cooling it down, it's gonna
hang around for enough time that you could have a
chance of grabbing onto it. And so a little calculation,
and he says, holy smokes, this looks like it's gonna work. And then I said, well, I
wanna refine the calculations. So then this was gradual eureka. I wanted to refine the calculation. So you're surrounding this atom with light and it looks like it's getting very cold, to the point where your feeble little trap that was gonna hold the atom could work, but it needed to hang around for awhile. So I said, tomorrow I'll come in and I'll start to write a program to predict how long it would hang around. I start to write the program. Luckily, I'm not that
good at writing programs and get through about three lines. (Harry laughs) Because if I was really
good at writing programs, I wouldn't have thought about it at all and just written a program. So I get the three lines of code and said, I've seen this problem before. Einstein solved it (both laugh) in 1905. - Good old Albert. - And what he did is he looked
at a dust particle in fluid and he was studying Brownian motion, and here's this dust particle and it's being battered from both sides by atoms and molecules, and he said, okay, if I take this particle and I move it, there's a viscous drag in the fluid, and that slows it down. And the reason it's being battered around is because of this random imbalances between pressure from the
left, pressure from the right. And what I wanted to calculate
was how this particle would wander around. Because the previous day I'd shown, it has this viscous drag on it and that you still have
these fluctuations. I was gonna write this
computer program to say, okay, stepping to the
right, stepping to the left, and balance all the forces. And I said, no, I can use his solution. I know where it is. It's in an elementary textbook,
an undergraduate textbook. It's the random walk in a Brownian medium, and you just plug in those numbers, and voila, you get, wow, it's
hanging around for a long time because it's a random walk. And so I got very excited and
went to my boss Chuck Chang and said, look, Chuck, I
know you're not keen on this after years of research, but this is so simple,
it has a shot at working. (both laugh) And then you can get it
cold, you can hold onto it, and we can go from there. And then I remember he thought about that and said, well, okay, you earned the right to do something crazy. But don't try to recruit someone else. (both laugh) So I said, okay, okay, just my postdoc and my technician and me. Again, because if you're
onto something really big, you wanna bring in your friends and say, okay, we wanna go
fast and we wanna do this. So we puttered along for a few months, going like the blazes, and then I talked to Art about it. He went hmm, hmm, okay. It's not the way I envisioned it, okay. Sounds promising. Then after a few months,
it began to look like it was gonna work, really gonna work, and I said, come on, join in. (laughs) And it's gonna be a lot of fun. And, again, as I indicated in my lecture, it worked much better
than anybody expected. - And what are the implications
of what you discovered in a layman's way of understanding? - Well, what you can do once
you get an atom very cold, and cold is really the average
speed that an atom moves. The atoms in this room
are moving at speeds of supersonic jet planes. In fact, that's why the
speed of sound is what it is. It's determined by the
speed of the molecules. Okay, once you get an atom really cold so it's moving as fast as an ant walks, that a fraction of an inch per second, then very, very weak forces
can push them around, and you essentially can do
what you want with them, for example, using electric
or magnetic fields or light, and you can hold them. You can push them around. You can do things that
you simply could not do when they're whizzing around
like supersonic jet airplanes. And the ability to hold onto and control and manipulate these
atoms means, for example, you can toss them up. They can turn around due
to gravity in a vacuum can where there are no other atoms around, and you can make better atomic clocks. You can make what are
called atom interferometer. You quantum mechanically
split the atom apart so one part is the quantum wave going in one region of space. The other part of the
atom is the quantum wave going in the other region of space. That atom interferometer
can be used to measure the acceleration due
to gravity or rotations with very high accuracy. In fact, in terms of
acceleration due to gravity, better than any other way of doing it, and in terms of rotations, certainly better than any commercial or even laboratory grade laser gyroscope. So all of a sudden, you can
measure changes in gravity so accurately that it's
gonna become competitive with the current ways of
measuring changes in gravity, which is used for oil exploration. You can probably put it on
an airplane or helicopter and with global positioning
satellite to tell you the height and changes in distance, and inertial sensing systems, and something that measures
change of gravity over distances on a scale of a meter, it opens up the opportunity
to map gravity gradients and pockets of oil, diamonds,
things of that nature, minerals, on a very fast moving platform like a slow moving plane or a helicopter. So they have some real
practical implications. Already the world is on
the atomic clock standard defined by so-called
atomic fountains of atoms. The atom interferometer
was totally unexpected. It just popped out after
we begun to realize, let me say that, people, even
the researchers in the field, it's hard for them to think
about what you can do with it, even if you force yourself,
until you have it in hand, and you can then begin
to see the abilities of this new method or technique, and then it's only after we had it, and not only me, my group,
but the world in general, no one was talking about
many of the applications that came out until we actually had it and we saw how powerful it was, and then began to appreciate it. And you can try to force yourself to think of what might come of it, and you can write down a few things, but you're gonna get a
small fraction of them, and that's the wonderful
thing about science. - And actually it hearkens back for me to what you had said about
your high school experience in a funny kind of way,
that sort of learning to look at something and
think logically about it, and, wow, you're sort of taking it to, not that you were doing Nobel
Laureate work in high school, but some of the elements
are there in this work. - Yes, I think that's true. But it's always also just
letting something happen. This is one of the things
I did learn at Berkeley, and I watched great scientists here, and many of them were doing something that in hindsight looked very natural. They would say, here's
an emerging technology. With this emerging technology,
can I ride piggyback on it? And can I use this technology
to turn it backwards and do some new science? Normally you think, oh,
basic new science discovery. It turns into a technology. You make a better widget. But what I appreciated when
I was a graduate student here was that's all true, but you can also take that
technology, turn it around, and you can use it, and
a good example is radar. During World War II, the US
and Great Britain especially developed microwave engineering methods to have microwave transmitters
that allowed radar so we could measure and
see things far away. And the scientists who
helped develop that radar and other scientists
who could see the power of that technology really seized on that shortly after World War II, and a string of Nobel Prizes came out of people who use this new
technology to do great science. Charlie Townes here is
a prime example of that. His knowledge of microwave science, he was, during the war,
working on microwaves. - [Harry] At Bell Labs, too, I've heard. - At Bell Labs, that's right. After the war, he said, I want
to do microwave spectroscopy because here's a new tool. We now have control of
shortwave radiation, and he became one of the real leaders in microwave spectroscopy, wrote a classic book with his
brother-in-law Arthur Schawlow and then invented an idea of stimulated emission of
microwaves called a maser that then led to the
extrapolation of those ideas from microwaves to optical
wavelengths led to the laser. And so that's one example of
first building on technology during the war, saying
this is a wonderful way, a new scientific tool. Use it to do science. Then wanting to improve the tool to get to shorter wavelengths and, voila, you have the laser. And I saw this over and over again. When Charlie came to Berkeley, he wanted to use his knowledge
in lasers and microwaves to do astronomy. So again he was gonna ride this technology and I was looking around and saying yes. Now, he's a brilliant scientist, but the lesson I learned was you don't even have to be brilliant (both laugh) if you're the first to look
at something with a new tool. So I began to say, okay,
what are the new tools? When I was a graduate student,
there was something called a tunable di-laser, and I told my advisor, this is a wonderful thing. It's only a few years
old and it's sort of like this is a tool that we should be using. Now let's go figure out
some science to do with it. And luckily, it turned out fortuitously that there turned out to be some very fundamental physics questions you can address using this tool. And it's the fundamental
physics that drove him, but from my side, yes, I was drawn to the
fundamental physics, but also let's use a new thing to do it. If you use an old tool
to tackle a problem, you've gotta be really smarter
than the rest of the folks. Because everybody has this tool. If you're the first to
look at something new, it's like discovering a new world. You just look around and everything you see is going to be new. - So bring this now to
where you're moving now, because you, in a way,
are going into biology. You already touched on that earlier, but you are bringing physics
to the table of biology, so to speak, and tell us a
little about what you're seeing, and you quoted Yogi Berra
yesterday about that, that it's amazing what you can see. - It's amazing (laughs). Well, Yogi is one of my heroes. As I've mentioned, he's really the great American philosopher for the 20th century. - (laughs) That's right. - And one of the things is he said you could see a lot by watching. He said other wonderful things like, "If you come to a fork
in the road, take it." - That's right. - Or, "We may be lost, but
we're making great time," and many, many things he said. (both laugh) But anyway, so my entree into biology was exactly what I was telling you about. I was working on atoms, cooling atoms, holding onto atoms with light. I said, well, the same technology can be tweaked a little bit, and we can maybe hold onto
individual molecules with light if you play some tricks. And what could you do with
these individual molecules? And then naturally I thought of biology. So naturally I thought,
well, let's first try to hold onto a piece of DNA. So strictly a technological thing. And so that worked, and
then as I had some ideas of looking at enzymes, proteins
walking up and down the DNA, and seeing what can learn in biology. But the first thing I
did is I got this thing and we glued little
plastic spheres to the ends of this big DNA molecule, so big that its length was
something like 15, 20 microns, which could easily be seen
in an optical microscope. Now you can't really see a piece of DNA because sideways, it's only 20 angstroms. It's not resolved by
an optical microscope. But you do a trick. You put little dye molecules,
fluorescent molecules. So think of it as a string
of Christmas tree lights. You can't really see the string. It's too thin, but you see
the light coming from that, and so it shines very nicely
in an optical microscope and you can move it around. So the first thing we did is,
okay, let's stretch it out. Wow, it stretched out. Well, let's see if we can break it. So we stretched it, stretched
it, harder and harder, and we couldn't break it. It's very strong along that dimension, which is good because it
holds your family jewels. You don't really wanna break it that way. And so in the end, what happened, it pulled out of the optical tweezers, these things we were using to hold onto these plastic handles we glued onto the ends of the DNA, and it sprang back like a rubber band. It just went boink and
it just crumpled back up and I said, holy smokes, it
looks like a rubber band. Why does it look like a rubber band? And the reason it looks like a rubber band is because when a molecule's straight, it's in very unlikely state. If left to its own devices, it's being battered
around by water molecules. It wants to sort of do
some random coil geometry. That's a much more likely state. And so the reason it springs
back has nothing to do with chemical bonds and
forces pulling it back. It has to do with whether
it's more likely to be found in some random coil or straight. It's the same reason if you push all the molecules of the air into a corner of the
room and let go of them, they don't even have to
bounce on each other. They would say, where would I likely be? Well, equally likely
anywhere in this room, and so the pressure
evens out very quickly. And that's why it was springing
back like a rubber band, and I said, well, now I can
do this on a single molecule, and what things can you do there? Well, you can understand polymers. Polymers are long, skinny molecules, but you can look at it one at a time. And so it was a backdoor
entree into polymer physics, and we did that for a half dozen years, and finally I started
getting back into biology because the things we were
finding out in polymers, well, this is unexpected. They all are behaving differently, even though they're put
in identical situations. They should do the identical
thing, but they don't. Well, maybe biology's not
as simple as we thought. And so I said, okay, let's
go back and look in biology. But it's the same thing. It was a little technical trick or two, but usually when you're doing
a technical trick or two in the past, you say, well,
I don't really know biology. There's a lot of fancy names
and it's a different culture, and so I'll develop the technique and hand it over to the biologists. But at this time, I wanted none of that. (both laugh) Why should they have all the fun? - And you're seeing even in
these early stages of your work that you were seeing a kind
of, what did you call it? A molecular individuation. - Right. - As opposed to looking at these things and reaching a conclusion on averages. - Right, right, and so, that's right. While doing polymer experiments, we found that molecules
act as individuals. In fact, they acted as
individuals with moods, meaning you think you
start with the molecules, it is precisely the same situation. You ask it to stretch. It would stretch in one way
with a particular geometry. You put the same molecule
back, same conditions, ask it to stretch again, and it would do something differently. And we realized finally with
doing computer simulations that the reason it was doing that is because it wasn't exactly the same because it's bouncing around. It's in water, Brownian motion, and so when you ask it to do something, it's sort of trapped in
its particular state, and if you ask it to do
something fairly rapidly, it doesn't have time to look
around and find the best path. It just does what it has to do. Imagine you're going down, you're in the Newark or Japanese subway. It's very crowded and there's
two subway trains, okay? And one's the right way,
one's the wrong way, but all you know is the doors
are gonna close very quickly. There's a mob pushing you from behind. You're not gonna make the right decision. (both laugh) You're gonna go with the flow. The fork in the road comes,
you're gonna take it. And depending on whether
you're a little to the left, a little to the right of this, you're gonna be pushed
forward into one of the cars. And so the same thing was
happening in molecules. Depending on the initial
starting condition, you're gonna take a certain
path that gets magnified. You start with a slightly different random starting condition, you're
gonna take another path. And the profound thing that was
affecting me, it's not that. That, once you think about it, is trivial, but that many things in biology, this is an out of equilibrium process, and many things in biology
at the molecular level might be out of equilibrium also. And then the way to look at it
is to look with these methods and then to think of the
non-equilibrium parts. And because we were trained
to think of an equilibrium because equilibrium things are things we could measure easily with the techniques that we had before. But now if you can follow a
single molecule and say, okay, non-equilibrium is a major part of this. So now we get to look at it, and we can look at how
molecules change their shape in real time. Well, so again, it's going
back to what I learned here at Berkeley. Use some new technology
and have a first peek. - One final question
requiring a brief answer, it's all been a random
walk for you, then, right? - Oh, absolutely. Right. - And so what recommendation
would you give to students looking on your life,
reflecting back on it, if they wanna prepare for science? - You've gotta be very
interested in what you're doing. You have to attack it with a passion. You can't give up. You have a plan, but if during the execution
of whatever plan you had, something comes along, keep an open mind. - On that note, Steven, I
wanna thank you very much for coming back to Berkeley
to be the Hitchcock Lecturer, but also thank you for
coming to our program and sharing your
intellectual journey with us. Thank you. - Thank you. - Thank you very much for joining us for this Conversation with History. (electronic music)
