Steven Chu
Nobel Physicist

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Steven Chu
Laser Super-Cooler

GS: Is that measurable by even the gyroscope that your grad student came up with?
SC: Very much so. It is measurable enough so that it is the major way oil companies begin to look for oil. They actually measure changes in gravity.

GS: Is that the new technology for oil exploration?
SC: No, it's an old technology. They use an unbelievably sensitive spring balance to measure changes in gravity. The trouble with the spring balance is that they drift in temperature, you've gotta constantly reset them. It takes weeks or months to lay out large areas. For each reading it takes thirty minutes, then you go a couple more miles and make another reading.

GS: So it wouldn't be that reliable.
SC: It is reliable, but it's very painstaking. It takes a long time to make these measurements. What is possible but not commercially available yet -- but I would expect to come in the next decade -- would be that you could mount one of these atom instruments on an airplane and you fly at low altitudes and you can make this mapping in hours instead of in time periods of days, weeks, months.
     It's much more precise that you don't have to spend that much time. They're atoms, so they're not going to drift. It has all these other advantages. It only requires that someone package it in a robust way but people are now working on it.

GS: You also mentioned diamond mines. With oil I understand there are certain geological formations but...
SC: Same with diamond mines. With oil, the rock with oil is less dense than solid rock. For diamond mines of a certain type called Kimberlite Pike, there's also huge change in density. There are commercial companies that actually use a combination of the global positioning satellites to tell you what the altitude of the airplane is and accelerometers to block out the acceleration of gravity. It is hard to differentiate. That's a general principle of physics. So you use accelerometers to cancel out the local acceleration of the airplane. Then you have your spring balance. And they have shown that there's a definite signature.
     They flew one of these over Kimberlite Pike in Australia and showed this huge signature. People were skeptical and they said, “You knew that diamond mine was there. Tell us something we don't know.&rduquo; They went back and improved their algorithm by a factor of two or three and they started flying over other parts of Australia and they found other signatures that look exactly like that. But they were in locations where there are no diamond mines. So they're not telling people where they are until they actually lay mining claims. They're not telling people what the algorithm is, the mathematical algorithm to get out the acceleration and everything. But the fundamental sensor is still the spring balance.
     What atom interferometers give you is the possibility that this could be ten or a hundred times better than that in a very robust package. So again, people are really seriously working on this now and I wouldn't be surprised if in one decade there wasn't some commercially available package.

GS: Do you get anything out of commercial applications that use this atom cooling? Do you get any royalties? Have you patented it?
SC: Stanford has a patent on the atomic fountain clock. Stanford has a patent on atom interferometers of this type based on optical pulses and measuring gravity gradients based on that -- which then you can rely on to look for oil. We have patents on holding onto individual molecules of DNA. The trouble with these patents is that they are so new, that there simply is no existing technology base. And that is one of the issues about radically new patents. By the time the patent is worth something, it's expired. So I think there was a few thousand dollars that Stanford got in some of these patents, maybe ten thousand. But it's only when it becomes widely commercially available that it's gonna be making a lot of money. With the patents on the atom interferometers, I'm not sure when they run out. My guess is I think we patented it in '93. It has a 17 year life. There's maybe six or seven years left. It's going to be very marginal.

GS: So you're working too far ahead of the curve to become rich.
SC: That's true. Look at the laser patent. It would have been issued in the early sixties. Its real money is now. The first 17 years there's not that much. But if you had the fundamental patent on the laser beginning now and you can hit all the people who use laser for communications, printing, medical applicationis, then it's worth zillions of dollars. So the really far out new stuff takes a long long time.

GS: What impact did getting the Nobel have on your work, your career, your life?
SC: I spend a lot of times doing things like this, much more than I would. So I get dragged down a bunch by other things,

GS: So viscous forces develop.
SC: That's right. The Nobel is unique in all the prizes in science. It really promotes you to center stage in the eyes of the non-scientific public and that means that most people feel there's a certain obligation to become a spokesperson for science. It's not universal but in most cases it's true; most people feel it's giveback time. So we spend much more time going to science fairs and science camps and talking to kids, things like that than I would have done.

GS: What about positive benefits?
SC: I look at that as a positive benefit.

GS: It is for the world, but in terms of your immediate efforts, have there been some positive impact from winning the Nobel? More access to resources?
SC: I would say that your particulars depend on the university. They either treat you like a demigod or wouldn't think of firing you.

GS: When you say treat you like a demigod, what do you mean?
SC: It depends on the university. I happen to be at a university that is spoiled. You can get your private parking space. There are professors in other universities that get private parking spaces. At Stanford no one gets private parking spaces. [laughs]

GS: Do you get better meals, better access to facilities? Do you see any benefits?
SC: No, that still is a meritocracy. It depends on what you're going to do next. You want to give the resources based on what they're gonna do next. You don't want to give a lot of resources to people who did great things 30 years ago.

GS: Is Stanford that strict a meritocracy that they don't honor people that bring honor?
SC: To a lesser extent than other Universities. As I said, we're spoiled. We had six Nobel prizes in physics alone in eight years.

GS: So you're just another one.
SC: Just another one.

GS: That's kind of sad...
SC: A good friend of mine who's a Nobel laureate in chemistry, he's now older, he's over seventy, he's about seventy-five. He's got a bad hip but still goes to work every day and was asking for a parking space next to the building he works in so he wouldn't have to walk so far. He's got a hip replacement. And the answer was no.

GS: That's cold.
SC: I said to him, Don't argue on the grounds that you're a Nobel winner. Argue on the grounds that you can't walk. He says, Oh yeah, I got a handicap spot. Well those are pretty good.

GS: You didn't get a bump in salary or something like that?
SC: Yeah, I did. But it was actually generated not by the fact I got a Nobel Prize. It was generated by the fact that all of sudden you become hot property elsewhere and so it's a free marketplace.

GS: Other universities don't necessarily have physics Nobel prizes and might like to get one.
SC: Especially if you're young enough that you still have active programs.

GS: What projects are you focusing on now?
SC: It's a mixture of atomic physics experiments. First, continuing to develop cooling techniques. The show is not over yet. There are new cooling and atom manipulation techniques that are still being invented. There are cooling techniques that're still being invented. Even in the last three years my laboratory has invented two new methods, and I think they're going to be generally applicable, widespread. And we're currently working on a path to get Bose-condensed atoms much faster than before. So instead of having to do it in thirty or forty seconds, we're hoping to do it in one second and that's kind of on the cheap. It's another tool, makes it easier and opens up technological possibilities.
     We're also trying to do some experiments with them that would be essentially studying new states of matter. We're also continuing to develop atom interferometers. In this case we're measuring the fundamental constant that determines the strength of electric and magnetic forces. That constant called the Feyn-Structure constant has been measured with great precision and what's nice about that is there are many ways of measuring the constant because electricty is one of the real fundamenal forces that we deal with on a day to day basis so it cuts across all of science and there are many ways of measuring it. And because of that it's really our best overall check of the overall consistentcy of the fabric of physics. Because condensed matter physics, nuclear physics, atomic physics -- they all have ways of getting at this. We think we can be ten times better than anyone else. We are now as good as anyone else. So we're pushing on that. And that again goes to devleoping this new instrument, the atom interfereometer to even higher precision. PAGE 6

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“There are professors in other universities that get private parking spaces. At Stanford no one gets private parking spaces.”