Press conference: Cornell and Wieman Answer Questions about the 2001 Nobel Prize in Physics

The following text is a transcript of a press conference hosted by JILA on October 9, 2001. Eric Cornell and Carl Wieman of JILA answered questions from reporters about the 2001 Nobel Prize in Physics, which they shared with Wolfgang Ketterle of the Massachusetts Institute of Technology. JILA is a joint institute of the National Institute of Standards and Technology and the University of Colorado at Boulder. The press conference was held at JILA, which is located on the campus of the University of Colorado, Boulder.

Thank you all for coming today. We have a few opening remarks before we begin. Our first speaker this morning is Elizabeth Hoffman, president of the University of Colorado.

Hoffman:
Good morning. This is an historic day for the University of Colorado.

As you all know, the Royal Swedish Academy, at 4 o'clock this morning, Mountain Daylight Time, announced that Eric Cornell and Carl Wieman, professors of physics and members of JILA were awarded the Nobel Prize in Physics for the year 2001 for discovery of the new state of matter called the Bose-Einstein condensate. They will share the prize with MIT researcher Wolfgang Ketterle.

This is the University of Colorado's second Nobel prize. In 1989 Tom Cech, professor of chemistry and biochemistry at CU Boulder, won the Nobel Prize in Chemistry.

Often researchers wait many, many years, often a lifetime, before being awarded the Nobel Prize for work that sometimes took place at the very beginning of their careers. We are so delighted that Cornell and Wieman have been awarded this prestigious mark of distinction so early in their careers. The fact that they succeeded in achieving this new extreme state of matter just six years ago and have already been honored with a Nobel Prize is a further testimony to the quality of their work and to the incredible quality of the research in JILA, in NIST, in the Physics Department, and at the University of Colorado at Boulder.

A few months ago, I presented to the Board of Regents a vision for the University of Colorado, CU 2010. Two items in that vision, the University without Walls and a Culture of Excellence, are exemplified by this gift.

The University without Walls refers to the bringing together of faculty across disciplines and, in this case, between the national laboratory, NIST, and the University of Colorado to do path-breaking research.

The importance of a laboratory like JILA and a partnership with NIST is in being able to free faculty to do research at the absolute boundaries of knowledge. It is also a demonstration of a culture of excellence. The University of Colorado at Boulder fosters, encourages, rewards excellence. These two wonderful faculty, JILA, and the partnership with NIST, exemplify that culture of excellence. Thank you all for coming today. We're just so thrilled at the outcome. Thank you very much.

[Applause]

Our next speaker is Susan Sutherland, director of the Boulder laboratories of the National Institute of Standards and Technology.

Sutherland:
Good morning. Thank you for offering me the opportunity to represent the National Institute of Standards and Technology at this very momentous occasion.

Let me just say how proud we are at NIST that Eric Cornell and Carl Wieman, together with Wolfgang Ketterle, have received the year 2001 Nobel Prize in Physics.

This is our second award in physics. In 1997 Bill Phillips of NIST won this award.
I am really relatively new to my position at NIST, but already I feel like I'm just standing on the shoulders of giants.

The body of research performed at NIST, JILA, and the university is enormous. And it is of the highest caliber. Today's award proves that. It also proves that Boulder has come of age scientifically. When some of my predecessors were planning JILA in the early 1960's, I am sure that they had in mind the type and quality of research that would someday earn this Nobel Prize. Their aim was to combine the best of both university and government research into one physical setting. And I would say they have succeeded.

But more than just the setting. I think that JILA can be summed up in one word and that is "freedom." From the start, both the government and the university scientists were given the freedom to pursue their interests, combining the best qualities of both the federal lab and the university. And the JILA Visiting Fellows program has brought the best minds from around the world to Boulder to collaborate with the JILA scientists. So in a very real sense today's award for a spectacular achievement in physics represents the flowering of research in this Boulder community.

All Boulder scientists, whether at the university, NIST, NOAA, or NCAR, can take just tremendous pride in Eric and Carl's success. Thank you again for allowing me to make these remarks. Congratulations, gentlemen.

[Applause]

Our next speaker is Richard Byyny, chancellor of the University of Colorado at Boulder.

Byyny:
Good morning and thank you. This is an absolutely wonderful day for the University of Colorado at Boulder. On behalf of the faculty, students, and staff on the campus, we want to congratulate the two of you and all the other people who we know made important contributions to this success.

Winning the Nobel Prize is clearly the ultimate recognition of the world-class research being done on our campus and it is the highest honor that can be received by our university and the state of Colorado. Carl Wieman, as many of you know, is a Distinguished Professor at the university and recently was named one of the seven scientists in the nation to receive the National Science Foundation's highest award for distinguished teaching scholars.

Eric Cornell is a Senior Scientist at NIST and is also a professor of physics here on the campus.
In addition to being recognized and acclaimed as atomic physicists who did the ground-breaking research they are being recognized for now—the discovery of a new form of matter—both teach undergraduates and graduates and are involved with students in research on the campus. Carl has already told us that he has to leave this conference in time to teach his 11 o'clock class this morning, which is a physics class for non-scientists, and whose members are mostly CU-Boulder freshmen. What a treat for them.

The other thing that I think this is a tribute to is the importance of basic research. When you think about how we make great discoveries in science that make a difference, it is really through basic research. Many people ask, "What is the importance of the research that is being done? How will it be applied?" And we don't know yet. If I were going to speculate, to get a chance to throw my little bit in there, I would say one of our great challenges is how do we build new molecules from individual atoms eventually. This is one of the ways that you begin to get at individual atoms and be able to think about how you then can build a new molecule that will have some potential benefit for mankind.

I also want to recognize that both Carl and Eric are fellows of JILA, one of CU-Boulder's research institutes and a joint institute with the National Institute of Standards and Technology and a wonderful example of the partnerships that President Hoffman talked about.

So it is my distinct honor to extend congratulations on behalf of the entire University of Colorado at Boulder, our campus, to the Nobel Prize winners here with us today, Carl Wieman and Eric Cornell. Congratulations.

[Applause]

I'd now like to introduce James Faller, chief, Quantum Physics Division, of the National Institute of Standards and Technology.

Faller:
This is really an exciting day.

JILA was formed in 1962. Thirty-nine years later we have this stupendous event.

Some of you might wonder how JILA was brought about. If you actually come from Duane Physics next door to JILA you reach a bunch of doors that have a sign on them which says, "Beyond this are no classrooms." So you actually might think that those who could teach might turn back. But in fact it is just the opposite. We have two outstanding student [inaudible] . . . focused on a culture of excellence. . .

What they have done is basically brought the smallness and the difficult to understand aspects of quantum mechanics, which is just strange physics at small sizes, into a macroscopically dimensioned thing that you could actually examine. That's basically what the condensate is that they have created. I congratulate the two of you.

NIST is extraordinarily proud. This is our second Nobel laureate by the way. Bill Phillips got the Nobel Prize in Physics also. It is a proud day for NIST, a proud day for the university. In the world we live in today, it is a delightful bit of sunshine that we have today here. Thank you.

[Applause]

Our next speaker who will be introducing the laureates, is Ellen Zweibel, chair of JILA, a joint institute of CU Boulder and the National Institute of Standards and Technology.

Zweibel:
Like everyone else here I'm really overwhelmed with joy for Eric and Carl. I'm proud to be at JILA. By the way, I hate to introduce a correction, but JILA only stands for JILA. It doesn't stand for Joint Institute for Laboratory Astrophysics or anything else that might occur to you. It's just JILA.

I am very grateful for the opportunity that they have and that we all have to work in a place like this.

There is a very old idea that pervades our culture that the people who can understand the laws of nature on a fundamental level are wizards. In fact we have a program for children on occasional Saturdays called the CU Wizards Program. The real magic here is that this understanding is not achieved by wizards, it is achieved by human beings.

So please join me in welcoming Carl Wieman and Eric Cornell.

[Applause] [Whoops and hollers] [Applause]

Cornell:
Carl, your prepared comments. [laughter ]

Wieman:
Eric's the quotable one, we'll let him go.

Cornell:
I can't tell you how thrilled I expect both of us are to be standing here on this particular occasion. It is a tremendous honor. And it really is something, I think, which reflects on the accomplishments of a great many people. The rules say that the Nobel Prize is to be given to at most three people. But in fact even if you were just to look in my lab or in Carl's lab, there are many more people than that who are working there and who actually really did the work. As you look around the labs, you see the amazingly capable staff of JILA, the scientific staff, the administrative staff, and our many really excellent colleagues who inspire us and urge us on to greater achievement every day. These are the sorts of things that happen around here. It is a place I'm proud to be associated with.

Wieman:
So, I think we really didn't have any prepared remarks. We're just happy to take questions.

Question:
Well, obviously how does it feel?

Cornell:
Pretty good. [Laughter.]

Question:
I mean, has it sunk in?

Cornell:
Only in little bits and pieces. I was sitting just in the front row here and someone said, "And here we have before us the Nobel laureates," and I'm looking, "Oh, where would they be?"

Wieman:
It is really an exclusive club that you've looked at your whole career, and it is kind of a shock to be a member of it now.

Question:
This has come early in your careers relatively—you both have a number of years left in your careers. Can you comment on that?

Wieman:
He has a lot more than I do. [laughter]

Cornell:
It's a very nice thing to be able to look forward, in fact, to yet some career to come I hope. I plan not to go to seed immediately. There are really a lot of things to be done. One of the more exciting things about Bose-Einstein condensation is that on the one hand it really represented, back in 1995, a culmination of efforts Carl and I had been really intensely engaged in for over five years. I now see, looking back over the intervening five years, that it really was the beginning of a tremendously exciting period of research for us. I don't think either of us really anticipated how many avenues would branch out from that one main road. There have been thousands of papers written on this topic now. Carl and I are authors of only a dozen or so of them. And both in terms of things that theorists have worked on and now with what approximately 30 other laboratories internationally are working on, each of these laboratories has found in most cases an entirely new niche, a new angle to study. I don't think we saw this coming, but it has been very exciting for us to have been there at the beginning of that.

Wieman:
It is also really fun that in our own labs every week there are more new, interesting things. It just keeps growing. There are always more interesting things to do. Our students, they are probably down in the lab working now.

Cornell:
As it should be.

Wieman:
It's been very rewarding for us in the small local area too—to have a new interesting area of science, to discover new things on almost a weekly basis. It is a lot of fun that way.

Question:
When you guys realized what you had discovered, were you immediately aware of the caliber of the discovery—that it might someday win a Nobel?

Wieman:
To be honest, yeah. [Laughter]. This was something that a lot of really smart people had been working on for a long time. And when we first saw it, it was unlike most scientific work where you first see some kind of little hint and you keep working and it gets better and a little better and you become more and more convinced. This just jumped right out at you, and it was just spectacularly clear it was there.

Cornell:
And that it was real.

Wieman:
That it was real. People around the world were all talking about it as the atomic physics "Holy Grail." So it was really exciting.

Question:
So it is not a total surprise that you're winning this, but how about the speed, doing it in only six years? How about that?

Cornell:
That was a bit of a surprise. I couldn't resist looking on the web. Over the last 10 years the lag tends to be closer to 20 years than six. Bill Phillips, of course, was an exception, as well. So I slept soundly last night, let's put it that way, not anticipating any early morning interruptions.

Question:
How did both of you find out?

Wieman:
By very peculiar ways, actually. I found out because my brother called and woke me up. And he found out by looking at the Internet.

Cornell:
It's not so easy to get our telephone numbers.

Wieman:
Which is one indication that we haven't exactly been out of the limelight for the past few years.

Cornell:
I got a telephone call from my old Ph.D. thesis advisor who called up saying, "Eric! I'm probably the tenth person to congratulate you!" I said, "No, you're the first person to wake me up." [laughter] Not that I was really upset, I must say.

Question:
What time was that?

Cornell:
4:15 a.m. local time.

Wieman:
I'm an old friend of his thesis advisor too. It may be the earliest he'd gotten up in the past 20 years.

Cornell:
He actually used that as a validation procedure. I said, "Dave, you wouldn't be pulling the leg of your old student would you? And he said, "You know I would not get up at this time for anything else." And he had a good point. I realized I was convinced then.

Question:
What are the potential applications of Bose-Einstein condensates?

Cornell:
Some applications are not at all pie in the sky, are rather immediate, but they tend to be fairly narrow. Of course, near and dear to the heart of NIST is making very precise measurements of time, length, distance—for both scientific but industrial reasons also, commercial reasons. Making atoms very, very cold. And in the end Bose-Einstein condensation is somehow almost like a limit of coldness for a dilute gas of atoms. Making these things very, very cold allows you to make very precise measurements of a great many physical quantities you might like to measure. In particular, time. Measuring time very well connects quite directly to measuring position very well. As most of you probably know, the breakthrough that enabled the global positioning system was greatly enhanced timekeeping. And as timekeeping gets better, the next generation of positioning systems will be better as well.

Those are, I would say, not at all fantasy. Those certainly will happen. Other more precision-measurement related things have to do with, very, very sensitive measurements of rotation. Very sensitive measurements of acceleration. Many of you may know that in commercial airliners gyroscopes are based on lasers. They have a laser beam which goes around and around in a circle and can sense whether the airplane is rotating. This they use to navigate the airplane. It is predicted that a gyroscope based not on photons—on lasers—but on atoms—based on an atom laser—should be, okay, picture a 1 with 10 zeros after it, 10¹⁰ times more sensitive to rotation. So the [increased] precision both in navigation and in sensing small gravitational anomalies which might arise from petroleum deposits, that sort of thing, should be significant.

Wieman
That's the official NIST line. [laughter]

Cornell:
And I am the official NIST guy. [laughter]

Wieman:
There are also other aspects. This is a wonderful system for basically studying these weird laws of quantum physics that govern how material behaves at the submicroscopic level. We've brought those up onto almost a human-sized scale. We can go down and poke and prod and look at this stuff in ways that nobody has been able to before. We're learning about basic quantum physics. And with that knowledge, you can see places where it's going to touch on many other areas. Smaller electronic circuits, as you get down to where quantum mechanics becomes important. Quantum computing. Things like that. This is one of the great things about it. It's a wonderful system for studying and learning basic physics.

Cornell:
Just following up on that. And now taking the official CU line. If the history of technology teaches us anything, it is that the future lies in the direction of the very small. What physics tells us is that the very small is the domain of quantum mechanics. When you get extraordinarily small, you have to take into account the fact that at the basic level, particles really act like little waves. You must understand quantum mechanics if you are to really make things smaller yet. Paradoxically, Bose-Einstein condensation, the stuff that we've made, is not especially small. Because we get the atoms so cold, it is almost like a quantum magnifying glass. The effects of quantum mechanics become immensely amplified until that you can see them basically right before your eyes.

Wieman
It is about the size of a human hair. If you want to get a size scale.

Cornell:
Which is pretty big on the grand scale of things. Therefore, really it becomes a laboratory, both a research laboratory and yes, a teaching laboratory for the world of quantum mechanics because you've brought it to the human scale. Indirectly then, perhaps the biggest impact on technology is that a deeper understanding of quantum mechanics will surely lead to a better understanding of very small things. The paradox is that our making quantum mechanics big may help in the development of things which are very small.

Question:
Can you guys talk a little bit about the work that won the Nobel prize five years ago, 1997, by your colleagues in Gaithersburg, because I understand that formed some of the underpinnings of your work?

Wieman:
However many years ago it was. Bill Phillips, Steve Chu, and Claude Cohen-Tannoudji. That was work for laser cooling, primarily. That's using laser light to shine it on atoms and get them very, very cold. The history is, we started studying laser cooling, and using laser light to cool atoms and laser trapping to hold these cold atoms, studying the processes involved in that, what limited how cold and dense you could get things. So that was very much working in the same field as they were and using a lot of their developments and ideas. That was kind of the springboard for us then to go onto the next step, of using that understanding, using those techniques, to make things much colder—cold enough to get to Bose-Einstein condensation.

Question:
Give me your thoughts on what it's like to know that you're the reason that the science books are all going to have to change now.

Cornell:
There's a certain sense that what we did is a very, very conservative almost sort of retrograde thing. The predictions of Bose-Einstein condensation were made by Bose and Einstein in 1925. Although I think it is a forward looking field, it has sort of a pleasant antiquity almost to it these days, by the standards of modern physics, to be confirming a theory which is so very old. I like that almost as much. Call me an old-fashioned sort of guy.

Wieman:
It really is satisfying that you open any textbook, and they'll have this chapter on Bose-Einstein condensation as something that was predicted but probably can't ever be realized in the real world. It is just kind of this physics construct idea that the textbooks all talk about as a neat idea. Now they have to go back and say, "Well, look it really can be made." That's pretty neat, I have to say.

Cornell:
Einstein himself in the late 20s later sort of conceded, you know, that this was probably a mistake. We ought to think of this idea as sort of a model. You can't really do it because once you get into the real physical world he didn't expect that it would ever be realized. He changed his mind in the 30s back again. He's allowed.

Wieman:
At the same time, it is also true that I don't think we would have gotten the prize, and certainly nowhere near as soon, if that just turned out to be all that we did. To show that, "Yeah, Einstein was right again." Lots of people have done that. It is really that it's turned out there are so many things you can do with it. It's wonderful new stuff to play with. That's really the reason for this prize.

Question:
The theory had been around since 1925. What was the barrier to actually proving it or realizing it, if it's that simple?

Wieman:
You had to get things down to a hundred billionths of a degree above absolute zero. That was vastly colder than anyone had been able to get before. You had to figure out how to get things just a whole lot colder. And at the same time you know, this is a little more technical, you know that if you cool off water vapor it condenses to form liquid and if you cool it further it turns into an ice cube. We had to trick this stuff into not turning into a little ice cube or a snowflake, as we like to call it. You had to keep it as a gas. Not turn it into a snowflake and figure out ways to cool it much, much further.

Question:
So, it was both the degree of cooling, plus the precision of cooling?

Cornell:
And playing a little trick on nature. Nature at that temperature really wants the gas to be a solid. In the textbooks of thermodynamics, the region where Bose-Enstein condensation occurs is always cross-hatched out, and the cross-hatch is labeled "forbidden zone." To go there, we had to go very deeply into the forbidden zone. We occasionally had to point out that that doesn't mean it is impossible. Theologically, it's important to point out that the things that are really impossible, they don't bother to forbid.

Question:
What enabled you to go that cold? What was the technology that enabled you to get this stuff that cold?

Wieman:
We did it in two steps. The first was you use laser light to cool and trap these atoms. You get it down to a balmy 10 millionths of a degree or so above absolute zero. So that was pretty darn cold to start with. But then you had to get rid of the light because it messed up getting colder. So we then turned off the light. To keep the atoms from falling and bumping into stuff and warming up, we held them in a magnetic trap, which is basically a magnetic field. Magnets with the right kind of field. And it holds these atoms incredibly gently. So it's like a great Thermos bottle. Then we use something called evaporative cooling. These techniques of magnetic trapping and evaporative cooling, as Eric was pointing out, there were a lot of other people who made important contributions. We borrowed that or copied those ideas from our old friend Dan Kleppner who had been working for many, many years trying to make Bose condensation with a different atom and using somewhat different techniques, not using laser cooling stuff. Once we got them held in a magnetic trap, we let the most energetic ones get out. The others get colder and colder. It's the exact same physics as how a cup of coffee cools. The steam coming off is the most energetic coffee atoms. The ones left behind get colder. Right? You know your coffee cools off. It just shows that the same physics can apply in very different places. That's basically how we did it.

Question:
How do you explain to your freshman non-majors, what is a Bose-Enstein condensate?

Wieman:
With lots of nice pictures.

Cornell:
Did you bring the pictures?

Wieman:
No.

Cornell:
So, you get the atoms very, very cold. Of course in a gas being very, very cold corresponds to going very, very slow. As atoms move slower and slower, they act less and less like particles and more and more like waves. This is the famous wave-particle duality that quantum physicists are always talking about. As they act more and more like waves, when you get to a point where the wave of one atom overlaps with the wave of its nearest neighbor, you get something which our friend Dan Kleppner has called a "quantum identity crisis." They can't tell each other apart. It turns out that the most natural thing for them to do is to all fall into the same wave. When sometimes people refer to this as a single superatom, what they mean is that the atoms are all participating in a single quantum wave.

Question:
They are atoms of what?

Cornell:
Rubidium.

Wieman:
If you have forgotten your chemistry.

Cornell:
And who of us hasn't?

Wieman:
The periodic table has a line of the alkali atoms. Sodium you've all seen because it's in these street lights. Glows yellow. Rubidium has the same structure. It's got one electron out there. It's easy to excite. That makes it good for laser cooling. Sodium is the same way. Sodium is good for laser cooling. Good for making Bose-Einstein condensation. Good for street lights. Rubidium's not so good for street lights because it's very deep red, its color for exciting that electron.

Question:
So Eric, why didn't you bring your bowl of BBs and show us that?

Cornell:
Were you here six years ago? We had some good props.

Question:
How long does the superatom state last and have you been able to extend that?

Cornell:
Quite a bit longer compared to six years ago. We now have had them stick around for a couple of minutes. It takes about a minute to make one. You make one and you get two minutes to play with it. Then it goes the way of all atoms and eventually does form the snowflake that nature intended it to be and then you make a new one.

Wieman:
Under various conditions it can go away a whole lot faster. Some of the interesting things we're studying right now are some things that make it go away extremely fast, far faster than makes any sense to us. That's sort of today's interesting, puzzling physics.

Question:
Do you keep working on the same rubidium atoms in a cycle or do you have to get new ones?

Cornell:
We have new ones. We've got a little metal container full of rubidium. It's interesting. It's put much
less than a gram of rubidium into the chamber in one of my labs. It's been in there continuously for four years. You don't need very many atoms to make a good condensate.

Wieman:
If you are a lay person, it is remarkable how far technology has gone. We have these samples with only 10,000 atoms in them. Which is just a tiny, tiny amount of atoms. We can see them very nicely on good modern TV cameras. They make a big, nice glowing ball there. No problem seeing 10,000 atoms. Whereas, a few years ago it would have been almost inconceivable to look at samples that small.

Question:
How can you see an atom if it's a gas?

Cornell:
If you shine light, which is exactly the right color for an atom to absorb, it absorbs that light and then actually spits it back out again. In particular, sodium atoms, if you shine exactly that sort of yellow, boring parking lot color, it would glow quite brightly. It wouldn't be so hard to see.

Wieman:
You wouldn't see the atom, you see the light bouncing off the atom.

Question:
What are you going to do to celebrate?

Wieman:
Go to Sweden? [laughter]

Cornell:
I hear it is lovely in December.

Wieman:
It's actually particularly exciting this year because this is the 100th anniversary of the Nobel prizes. They usually throw a pretty good party, everybody says.

Cornell:
I hear it's going to put the previous parties to shame.

Question:
So are you going to celebrate tonight?

Cornell:
I've got a sitter. [laughter]

Wieman:
I haven't thought that far ahead yet.

Question:
Is it worth telling them about the Physics 2000 website?

Wieman:
If you want to get a much better idea about how this stuff works and some of the techniques, there's a web site that we developed in the Physics Department. If you go to the Physics Department there's is a link to it. It covers a whole bunch of stuff. There is a section in it on Bose-Einstein condensation where it's got lots of interactive Java applets.

Cornell:
Little computer games. It's fun.

Wieman:
It gives you a whole lot better feel for how all of this technology works and how we look at this stuff.

Question:
What are you going to do with the award money?

Wieman:
To a physicist the award money is not . . .

Cornell:
Because we're such ascetics. [laughter]

Wieman:
The money is nice, but it's not really the reason you long to get the Nobel Prize if you're a young physicist. I haven't really given much thought or concern to it.

Question:
What are you going to be telling your students when you go to class at 11 o'clock?

Wieman:
I wasn't going to tell them a whole lot. I was going to tell them about buoyancy forces and how boats work and float and tell them to try to ignore the people hanging around the back of the room taking pictures. [laughter] And I really hope the demonstrations work when I didn't get a chance to practice them like I normally do.

Question:
What has JILA enabled you to do that would be impossible if there was just the university or NIST?

Cornell:
First and foremost, it lets Carl and I work together in a very natural way. I'm a federal employee. He's a state employee. Here we are, sworn enemies, and yet we're in this neutral ground here called JILA. It is a wonderful place, because it really does allow the resources of a federal laboratory to meet with the excitement of the university environment where you have students, postdocs, the young people that make up the university. It's a wonderful combination in that respect. JILA in particular is a place which really fosters and encourages collaboration between senior people which doesn't always work so well. Of course, it works everywhere in the University of Colorado, but in the brand X universities it can be a problem.

Question:
How old are you guys?

Cornell:
I'm 39.

Wieman:
I'm 50. [shrugs] [laughter]

Any other questions?

Thanks for coming.