C reative
Particle
Higgs
CPH Theory is based on Generalized light velocity from energy into mass.
CPH Theory in Journals
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Nobel 2001
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Bose-Einstein Condensation and the Atom Laser Bose-Einstein Condensation in a Dilute Gas "for the achievement of Bose-Einstein condensation in dilute gases of alkali atoms, and for early fundamental studies of the properties of the condensates"
Autobiography: Eric A. CornellI was born in Palo Alto, California in 1961. My parents were completing graduate degrees at Stanford. Two years later we moved to Cambridge, Massachusetts, the city I consider to be my hometown. My father was a professor of civil engineering at MIT, and my mother taught high school English. The family, including my younger brother and sister, accompanied my father on sabbatical years to Berkeley, California and Lisbon, Portugal. These were wonderful experiences for me and no doubt they are in part to blame for my lifelong love of travel. My mother taught me to read when I was still quite young, and at least in my memory I passed the majority of my childhood reading. My head was always bubbling over with facts and it seems to me this had little to do with my paying close attention in school and more to do with my voracious and omnivorous reading habits. Indeed in elementary school I often kept my desktop slightly open and affected an alert-looking pose that still allowed me to peek into the desk where I kept open my latest book, as interesting as it was irrelevant to the academic subject at hand. Every so often my hand slipped surreptitiously into the desk to turn the page. In the intervening three decades I have spent plenty of time lecturing in front of a classroom of my own, and in retrospect I realize I was seldom fooling anyone. Most of my teachers probably found I made less trouble if they let me read. Some nights, especially in the early summer when the late evening light kept my west-facing bedroom from getting very dark, I had trouble falling asleep at my appointed bedtime. My parents probably felt that reading me a story was a little redundant, but on occasion my father would come in and suggest to me a "problem" to think about. Stewing over these problems was supposed to help me go to sleep. It never did that, but it did get me in the lifelong habit of thinking about technical issues at all sorts of random moments in my daily life, and not only (or even primarily) during scheduled "thinking time." Some of my father's bedtime problems I now recognize as classic physics brainteasers. A man driving a van full of beehives comes to a bridge. The combined weight of the truck, bees, and beehives barely exceeds the safety limit of the bridge. The driver comes up with the idea of banging on the side of the van, so that all the bees swarm out of the hive and fly around in the back of the van. Does the fact that the bees are now all airborne make the truck light enough to safely cross the bridge? Other problems were exercises in mental estimation. If you hold out your thumb, at arms length, you can just about cover the moon with your thumb. The moon is a quarter of a million miles away. How big is it? The 1970s, the decade of my teenage years, was a transitional period in American youth culture. It was already past the peak of the era when science-minded kids built radios, model airplanes, rockets - things of that sort. But it was certainly well before the heyday of computers and video games. I was partly old-fashioned and partly modern. I certainly remember building model rockets. It was fun to watch the rocket blast into the air, suspenseful to wonder if the parachute would open to bring the rocket safely back. I didn't really enjoy the assembling the model kits very much, and usually I couldn't be bothered to paint the thing, or even to stick on the decals. A more vivid memory for me was designing a model of my own. Besides the store-bought kits, the Estes Model Rocketry company in those days also sold by mail various sizes of cardboard tubing, balsa-wood sheets, nosecones, and gun-powder rocket engines. Estes also published a terrific little booklet full of quantitative design tips. A key issue in rocket design is to make sure that the center of mass is well forward from the fins, lest the rocket be aerodynamically unstable. My father showed me how (after a candidate design was laid out on graph paper) to calculate the center of mass of the assembly based on the masses and distribution of the component parts. I designed an over-sized, under-powered, clunky sort of rocket. I didn't care how high it would go - I wanted it to rise slowly enough that I could watch to see if its orientation wobbled during the flight. On its maiden flight it lifted off the ground with all the ponderousness of a Saturn V, rising steady and true but rolling slightly about its long axis (had I glued the fins on crooked?) as it gained altitude. The engine burn completed, and then the parachute popped and my creation drifted with the wind to land on the roof of a schoolhouse. My parents suggested I go on Monday morning to ask the school's janitor to retrieve my rocket, but this I was too shy to do. My freshman year of high school I joined the chess and math clubs. The clubs met after school in the computer-instruction classroom, under the loose supervision of a genial polymath with the unlikely name of Mr. Wisdom. Between rounds of speed chess I read enough of a programming manual to teach myself to write programs on the school's DEC mainframe in the language Basic. For several months I was really captivated with this new activity. The exercises in the Basic manual seemed pretty tedious so I invented a few projects for myself, including a program to generate word puzzles for the math club newsletter. After a semester or so, my infatuation with computers burnt out as quickly as it had begun. Not enough substance there to sustain interest, I felt. This episode is probably the basis for my lifelong distaste for "computers for computers' sake" - it's a kids' game, I think. A second legacy of my brief childhood infatuation with computers was a life-long secret preference for programming in Basic, although during my years of apprenticeship in other scientists' labs I was compelled to learn both C and Fortran. When eventually I had the opportunity to establish a lab of my own, one of my first acts as a young principal investigator was to write a program to output a precisely timed sequence of electronic pulses to control the lasers and magnetic fields in what was to become the first successful Bose-Einstein condensation apparatus. Of course, I wrote the program in Basic! Some of my classes in high school were pretty interesting and I benefited from having several very intelligent and inspiring teachers. Among these were John Samp, a physics teacher, and JoAnn Walther, an English teacher. After the Nobel Prize announcement, I got back in touch with them and was delighted to learn that they are still (as of 2001) teaching at my old high school. Just before my final year of high school, my brother, sister and I moved with my mother to San Francisco. I spent my last year of high school there, at Lowell High School. Lowell High was a so-called "magnet school," drawing academically inclined students from all over the city. My fellow students there were very smart, but the really novel thing was that they actually seemed to put a lot of effort into their school work. By the end of my first semester there, I began to get into that habit as well. Something else new at Lowell was that it was "cool" to excel at school, at least among the Asian kids with whom I mostly hung out. Without the transitional year at Lowell, my first year as an undergraduate at Stanford would have been a horrible shock. The truth is that first year at Stanford was a shock anyway, although not for academic reasons. Everyone was beautiful, self-confident, self-satisfied. Later I moved into a student-run, co-op house and felt more at home in that "alternative" residential atmosphere. It was there I met my future wife, Celeste Landry, although our lives took us separate ways for many years and we were not to marry until more than ten years later. My first job in physics was as a "scanner" at the Stanford Linear Accelerator Center. As a freshman I needed to earn a little money and I was looking for a way to learn about science at the same time. The advertised hourly wage was unusually high for a campus job, which should have been a danger sign. On my first day on the job, a postdoc spent 30 minutes or so showing me how to call up symbolic representations of an endless series of archived detector "events," for display on a graphics terminal. There was a particular kind of rare event I was to look for - I can't remember now exactly what it was - characterized by a certain precise number of photons, of muons, etc. The postdoc explained to me how to distinguish different sorts of particles on the basis of the amounts of energy they deposited in various sorts of detectors, spark chambers, calorimeters, what have you. When I recognized a promising event, I was to flag it by pressing a certain key on the terminal, and, "pop", another event would come up on the screen for my consideration. After my 30-minute training period was up, the educational part of the job (and incidentally the part of the job involving any human interaction) was essentially finished. I could come in whenever I wanted, work as many hours as I wanted. The money was great but towards the end of the third mind-numbing afternoon of staring at the graphics terminal I realized my sanity was at risk. I decided to quit right then and there, and wandered around the data center looking for someone to notify of my decision. There were plenty of people buzzing around the room, but no one looked familiar. It occurred to me that, after the original 30-minute training period, I had never again seen the postdoc who had taught me the tricks of the high-energy physics trade. Finally I just wandered out of the building, never to return. Over the course of my three afternoons I had worked my way through hundreds of stored events, and flagged four of them as promising candidates. Is it possible those four events eventually got my postdoc a nice assistant professor position at the University of Chicago? One can always wonder! Meanwhile, I was taking freshman physics with Blas Cabrera, then only in his second year as a professor, and eventually I worked up the nerve to approach him after class. Did he have a position in his lab for an undergraduate? He did! I started off building some data acquisition electronics for a scanning magnetometer, sharing a lab bench with a fellow undergraduate, Charlie Marcus. For the remainder of my years at Stanford I worked afternoons and summers for low-temperature physics groups on campus. I really enjoyed this experience, and it was these jobs, more than anything else, that persuaded me to pursue a career in scientific research. Roughly halfway through my undergraduate years, I began to worry that my future was choosing me, instead of the other way around. Time seemed to be accelerating. Had I really already completed nearly two years of college? I was taking lots of science classes, spending lots more time in physics labs, and was doing well there. In a little more than a year, the most natural thing for me to do would be to apply to physics graduate school. Doubtless I would be admitted, and then - zoom - off I would go into a pre-defined future as a scientific researcher. It seemed somehow too pat, too canned. When was it that I actually got to decide the course of my own future life? Perhaps I would be happier pursuing something a little more explicitly intellectual than physics. Maybe a return to my first love, of books, was in order. I had been studying Mandarin Chinese for a quarter or two. I took a great interest in politics. Couldn't I put together some sort of future with all that in mind? The first thing I needed was to buy a little time to think it over, lest I be out the door with a degree before I knew what had happened. A Stanford program called Volunteers in Asia seemed to offer me that time. So the summer following my second year of college, I went off to the YMCA in Taichung, Taiwan, to teach conversational English. The work was pleasant and not very hard; I had a lot of time to read and to think and to study Chinese. Six months after that, I left Taiwan, first for Hong Kong and then for mainland China, where I spent another three months studying still more Chinese and generally kicking around the country. Travel provided many interesting experiences, but perhaps the most useful lesson I learned was that I really had no proficiency for learning the thousands of characters of the written Chinese language. It is not that my memory is generally poor. I am very good at remembering the lyrics to popular songs. A single line from a popular song probably represents about as many bits of information as a single Chinese character. If I could have displaced the one set of information with the other, I would have had no problem storing in my brain the 5000 characters necessary for advanced Chinese literacy. As it was, I realized choosing the study of Chinese literature as my life's work was probably a mistake. Conversely, I came to realize that being good at something is hardly a reason to avoid doing it. I returned to Stanford with much more of a sense of purpose. I continued to take elective courses in such topics as poetry and political science, but I allowed myself to enjoy my physics courses and my work in the labs. My last two years at Stanford I worked for the gyroscope-based general relativity experiment of Francis Everett and co-workers, with my final year's work growing into an honors project. Everett was the titular advisor of my honors thesis, but I worked more closely with John Turneaure, a research professor. The gyroscope relativity experiment needed data on the low-temperature adsorption properties of helium on various technical materials such as OFHC copper, fused quartz and so on. I inherited a recently abandoned apparatus and was told to extend the range of temperatures and go beyond monolayer coverage. I went to see John for advice as needed, but other than that I was left to work alone. No doubt I wasted a lot of time reinventing the wheel, but I loved the sensation of "having my own lab." For graduate school I returned to Cambridge. In the spring of 1985, shopping around for a graduate school and a research project, I met Dave Pritchard at MIT. He spun me a wonderful yarn: by very precisely measuring the mass difference between the helium-3 and tritium, one can determine the total amount of energy released in the beta decay of tritium. Combine this mass measurement with a determination (no big deal, Dave implied) of the endpoint of the beta-ray spectrum, and one has measured the rest mass of the electron neutrino! There were hints, in those days, that the neutrino might have a rest mass as large as ten eV, a value of cosmological significance. Think of it, Dave said: working with two or three other students on a bench-top experiment, one might just find the missing dark mass and close the universe! It sounded awfully good to me. It still does, as I retell it today. Thus in the fall of 1985 I joined Dave's single-ion cyclotron resonance experiment. The idea was to trap a single ion in a Penning trap, measure its cyclotron frequency to great accuracy, then swap in a different species of ion and do a comparison measurement. The ratio of cyclotron frequencies should be just the inverse of the ratio of masses. Two graduate students, Robert Weisskoff and Bob Flanagan, and a postdoc, Greg Lafyatis, had the apparatus designed and largely assembled by the time I arrived, but we didn't succeed in trapping and detecting single ions until three years later. The work got to be pretty frustrating and when at last one morning Robert finally acquired the definitive signal from a single ion, he said "That is that." By that afternoon he had begun writing his thesis and he did not return to the ion lab again. A new graduate student Kevin Boyce had recently joined the group and the two of us spent a couple of years learning how to make precision measurements on the single ions. It is hard to overstate how much I learned from Dave Pritchard over my five years as a graduate student. He was seldom in the lab, but he ate lunch with us students several days a week, and held regular progress meetings as well. Meeting with Dave could be a fairly overwhelming experience. He frequently was in a sort of quizmaster mode, in which he peppered his student with questions. "How big is this effect? You don't know? That's fine, but why don't you estimate it for me then? No, don't offer to go away and think about it - work it out right now, out loud, for the benefit of all of us here." His quiz sessions could be aggravating or even intimidating, but in the end I found them to be great training. Dave liked to show us how widely disparate effects in quantum and classical physics could be understood with the same basic and rather small set of ideas such as resonance, adiabaticity, stationary points, dressed states, entropy and so on. To this day I have ambitions of designing a course called "The Seven Most Useful Ideas in Physics," that would somehow condense and codify the Pritchardian wisdom. Thus it was that when my five years of grad school were over, while I had come nowhere near to finding the Universe's missing mass, I still felt enthused enough about physics research to proceed on to a postdoc. There are relatively few experiments in atomic physics these days that don't involve the use of a laser. One major shortcoming in my graduate education in preparing me for a career in atomic physics research was that I had not learned any laser techniques. I felt my postdoctoral job had better fill in that lacuna. Looking for a postdoc job, I made the usual rounds, visiting Yale, Stanford, Bell Labs, Gaithersburg, and so on. Laser cooling was in its heyday in 1990, and as I traveled around I saw all the major programs. I was a little daunted by the size and complexity of the experiments, and worried also that maybe all the really interesting experiments had already been done. Finally, I went out to Boulder to give a talk to Dave Wineland's group in NIST labs. Dave Wineland was and is one of the towering figures in ion trapping, so I felt a little foolish, earnestly describing to his group my modest contribution, but I soldiered on through my talk. No job offer was forthcoming, but as luck would have it, in the audience was a former Wineland-group postdoc, Sarah Gilbert. Sarah called her husband, Carl Wieman, who was looking to hire a postdoc, and suggested that he invite me to make the one kilometer trek from NIST labs over to JILA, on the University of Colorado campus, to visit his lab. At this time the main focus of Carl's research was on precision measurements of parity violation in cesium, but my attention was immediately drawn to his smaller, laser cooling experiment. In contrast to the other laser cooling experiments I had seen, which took up the better part of a room, Carl's experiment could have fit on a card table. Using diode lasers instead of Ar+-pumped dye lasers, and using a tiny little vapor cell instead of an atomic beam machine, the whole experiment seemed accessible and compact, even cute. There was just one graduate student working on the project, and this impressed me as well - if a single student could make it work, how hard could it be? (It would be almost a year later before I realized that Chris Monroe was not exactly an average graduate student!) It was clear to me that during a two-year postdoc I could learn how to make a fun little laser-cooling set up like Carl's, and, looking ahead, it also seemed to me that I could duplicate such an experiment as an assistant professor without much trouble. It would be sufficiently easy to constract that that I would have energy, time and money left over to use the cold atoms in turn to study something else; I would not be compelled to catch up with the established major AMO groups that were studying the cooling process itself. With an offer from Carl in my pocket, I went back to Cambridge to write up my dissertation. While considering the offer, I began to think for the first time of attempting to see Bose-Einstein condensation (BEC). BEC was a natural thing for atomic physics student at MIT to think about: occupying the office next to Dave Pritchard was Dan Kleppner, co-leader (with Tom Greytak) of one of the major groups attempting to see BEC in spin-polarized hydrogen. The idea of BEC was in the air, and I had seen a number of talks on the topic. Just a year earlier the MIT BEC group had dramatically succeeded in implementing evaporative cooling out of a magnetic trap, a clever idea due to Harold Hess. The MIT hydrogen experiment was daunting in its size and complexity, whereas it seemed to me that if one took as one's starting point the relatively tractable vapor-cell, laser-cooling technology that Wieman was using, it wouldn't be so much of a stretch to imagine souping it up into an apparatus capable of evaporatively cooling to BEC. So I decided to head off to Boulder for a couple of years. After accepting Carl's offer I postponed actually moving to Boulder for three months while my then girlfriend finished her PhD as well. In the meantime I took a very short-term postdoctoral position working with Joel Parks at the Rowland Institute, helping him design and build a Paul trap for ionized atomic clusters. In October of 1990 I arrived in Boulder. I found working with Carl to be a very congenial experience. Carl and I share very similar tastes in what makes for an interesting physics experiment, and I was happy to assimilate a fraction of his seemingly endless bag of technological ideas. Carl taught me to decide what part of the experimental apparatus really mattered, and then to spare no effort improving that part. Conversely, Carl emphasized that one needs to recognize where "good enough" was indeed good enough, and to waste no time worrying about it. I learned from Carl's student, Chris Monroe, as well. I had always been reluctant to mess with the innards of a store-bought piece of equipment, lest I break something. Chris' ever-fearless attitude was, if that gizmo isn't doing what we need it to do now, how much worse off will we be even if we do break it? As my two-year postdoctoral appointment wound up, Carl, Chris and I had essentially defined what needed to be done to make BEC with the hybridized method of laser cooling followed by magnetic trapping and evaporative cooling. During those early years in Boulder, I spent a lot of time trying to imagine what a Bose-Einstein condensate would be like, if we could ever make one. Would it be superfluid, like liquid helium? Would it be coherent, like a laser? What do "superfluid" and "coherent" really mean? I understood these words in the context of the experiments the words had been invented to describe, or at least I thought I did, but it seemed to me that to understand how these words applied to a dramatically different physical system, one had to have a much deeper understanding. Superfluidity and lasing were two of my favorite topics in physics, but each was surrounded by a vast thicket of lore and literature. It was hard to step off of the well-worn paths through these thickets, hard for a newcomer to get a fresh look at the underlying phenomena. If one could make a gas-phase condensate, one would have a less brambled system against which to test one's own physical intuition. Meditations along these lines converted me from BEC dabbler to true believer. It was with some zealotry, then, that I took the "hybrid cooling to BEC" pitch on the road in 1992, in an effort to find a faculty job. Berkeley and MIT did not bite, but I had offers from Haverford College, University of Virginia and JILA/NIST. The environment at JILA for doing AMO research was so strong, I decided to accept their offer and remain, against the advice of several people who pointed out the potential risks of remaining in the shadow of my postdoctoral advisor. As it turned out, over the years Carl was to be extremely fair in the sharing of credit, and I have never regretted my decision to stay at JILA. The scientific developments from 1990 to 1995 leading to BEC are discussed in the companion article. In the mid-1990s I ran a secondary research project in parallel with my BEC effort. The idea was to extend the techniques of laser cooling into solid-state systems. We never got it to work. In the end, my sunny optimism was trumped by my complete lack of training in solidstate spectroscopy. As it turned out, a group at Los Alamos National Labs has since successfully cooled a solid using a related experimental approach. Also in the mid-90s, Dana Anderson and I began a project to construct waveguides for matter waves. Our first successes were based on hollow glass fibers, but our ongoing collaboration now focuses on guiding atoms with the magnetic fields from lithographically patterned wires. The bulk of my group's research efforts over the last seven years has focused on elucidating the properties of BEC. With every passing year, BEC proves that it still has surprises left for us. Most lately my group has been pursuing studies of quantized vortices in BEC and of spin-waves in ultra-cold atoms. This latter work required us to retreat back above the BEC transition temperature! (Although we are still comfortably within a millionth of a degree of absolute zero.) I have been very fortunate over the years in the graduate students and postdocs who have come to work in my lab. Their hard work, talent and creativity have made me look good. I have been fortunate also to live in a society that values scientific research, and is willing to support people to do it. In 1993, Celeste Landry and I rekindled an old romance and we were married in January of 1995, in the Stanford Faculty Club. At the time of our wedding, I had upcoming professional travel to the ICOLS conference in Capri scheduled for June, and we planned to delay our honeymoon until then. Just two weeks before the ICOLS conference, the BEC experiment finally succeeded. In beautiful Capri, with lovely Celeste, I felt on top of the world. The next year I experienced a still keener pleasure, attending the birth of our daughter, Eliza. Her younger sister, Sophia, arrived in 1998. The four of us live in an old brick house in the shade of two large silver maples in central Boulder.
Autobiography: Wolfgang Ketterle I was born on October 21, 1957, in Heidelberg, a small town in Germany with a charming old city and a famous castle. My parents had come to Heidelberg after the second world war, when many people relocated within Germany searching for better economic opportunities. My mother's parents were farmers in Silesia, which has now become part of Poland. My father grew up in Memmingen, a small city in the southern part of Germany, where his parents had a canteen. I enjoyed a childhood of stability and peace, in contrast to my parents who had grown up amidst the conflicts of war. When I was three, we moved from Heidelberg to the village (now city) of Eppelheim, three miles away, where my parents still live. I grew up with an older brother (G�nter, 15 months older) and a younger sister (Monika, three and a half years younger). My parents worked hard to provide security and prosperity for our family. My father first joined an oil and coal distribution company as an apprentice and retired as a director. My mother ran the household and cared for the children; later, she managed a small business distributing first-aid products. In our family, work was not regarded as sheer necessity, but as a defining feature and rewarding aspect of life. My parents supported all our interests in music, sports and sciences. As they hadn't been exposed to many of these activities themselves, they did not steer us in certain directions, but rather observed our interests and then reinforced and supported them. That may be one of the reasons why my brother and sister are successful in quite different areas: finance and education. My explorations of the technical world started with Legos, with which I was quite creative in constructing moving objects with the basic building blocks that were then available. (Legos have become much more fancy since then!) I remember playing with electricity kits, doing repairs of household appliances, and using my father's power tools for woodworking projects. Explorations into chemistry were done in our basement, sometimes with friends, and my parents must have had quite a bit of confidence in my abilities when they allowed me to experiment with explosive mixtures. (I was quite impressed when such a mixture was able to melt metal.) Other projects included taking old radios and a TV set apart and combining a portable radio and a vacuum tube audio amplifier to create stereo sound. I was interested in learning more about electronics, but I was disappointed that the electronic kits explained only how to put the parts together, not how they really worked. So although I explored technology and science as a child, I didn't penetrate very deeply, partially because nobody guided me, and partially because I spent a lot of time on school and sports.
I attended elementary school in Eppelheim and Heidelberg, and then grammar school at the Bunsengymnasium in Heidelberg. My science classes didn't involve laboratories and the variety of projects and science fairs which my children now enjoy at their schools, but they were instructive and kindled my interest. There was one mathematics teacher, Albrecht Strobel, who was inspirational. He challenged me with special problems, and tried to teach the class to approach mathematical problems in a playful rather than formal spirit. Science and mathematics did not require much of an effort for me, but I worked hard to get the highest grades in languages and other subjects. As a result, I was the best student in my class. As a student, I liked to play soccer and basketball, and I also enjoyed trying out the various disciplines within track and field. My focus became longdistance running, but I competed occasionally in pole-vaulting. There was a year when I ran five times a week, but my talent was limited; I was occasionally well placed at town-wide events, but never in regional competitions. Still, I have maintained a passion for endurance sports until the present day. When I was around thirty, I met my own personal challenge and finished a few marathons under three hours, and I have completed many long bicycle tours. It was clear to me early on that after high school I would go to university to study either physics, mathematics, or computer sciences. I decided on physics, as I thought it would combine the real world and mathematics. At that point, I lacked a clear idea of what modern physics was about, but my initial enthusiasm survived when I learnt more about my chosen area. Before starting university, I received a fellowship from Studienstiftung des Deutschen Volkes (German National Merit Foundation). Part of the fellowship was the opportunity to attend special summer schools. The summer schools took place in the Italian Alps and introduced me to the beauty of mountains and to hiking. It has been one of my favorite activities ever since. Most importantly, those schools brought together a select group of highly talented students. The interactions with them reinforced my motivation to set high goals in life for myself. In 1976, I entered the University of Heidelberg, my home town. (This traditional university was founded in 1386 as the second German university.) It was clear to me from the outset, however, that after passing the pre-diploma (intermediate exam) in two years time I would transfer to another university and leave my parents' house. My choice was the Technical University in Munich because Munich is one of the most attractive towns in Germany and because the Technical University is excellent in many different subfields. At this stage, I wasn't certain what I would specialize in, and had only a diffuse notion of my current field, atomic physics.
Starting an independent life in a new town was a formative experience. The proximity to the Alps was an invitation to go hiking in the summer and skiing in the winter, and I loved both the small and big theaters in Munich and its arts museums. I also became involved with the peace movement and a group working on third world issues.
At the end of my diploma studies, I was very interested in theoretical physics and did my diploma thesis on spin relaxation in disordered materials under the supervision of Prof. Wolfgang G�tze. I learnt a great deal from his lucidity in analyzing problems and how he obtained physical insight from mathematical solutions. The thesis project took one year and at the end I found myself at a crossroads. Up to this point I had been focusing on purely academic problems, and now wanted to gain experience with applied physics and how it connected with problems of the real world. Therefore, for my PhD. I chose an experimental project, trace analysis of semiconductors using laser spectroscopy. This project was supervised by Prof. Herbert Walther and Dr. Hartmut Figger at the Max-Planck Institute for Quantum Optics in Garching. After one year, it became clear that this project was too difficult to be carried out within the existing infrastructure. Since I didn't want to start over from scratch, I continued my Ph.D. in the same laboratory, and focused on the basic spectroscopy of small molecules. We generated excited neutral molecules by charge transfer to a mass-selected ion beam. This gave us much higher selectivity in observing certain molecules than the usual discharges, and we obtained almost pure fluorescence spectra of triatomic hydrogen.
Towards the end of my PhD, I applied the same method to helium hydride and observed the first discrete spectra of this molecule confirming its existence. Helium hydride is the simplest heteronuclear molecule (besides HD), yet its spectrum had not been observed. I remember my excitement when I produced helium hydride for the first time and rotated the grating of the monochromator used to record its spectrum, and there was light almost everywhere in the visible and near infrared spectral regions. In the next few months, I would decipher some of those spectra and obtain first values for the bond lengths and vibrational frequencies of this molecule. It was exciting to determine the basic properties of a new molecule, like in the old days when molecular spectroscopy was established. After earning my PhD, I stayed at the Max-Planck Institute as a postdoc, working on laser excitation of Rydberg states of triatomic hydrogen and helium hydride. I also succeeded in analyzing all the emission spectra of helium hydride, which I had discovered during my Ph.D. The analysis of the spectra was complicated because the rotation of the molecule leads to a break-down of the Born-Oppenheimer approximation known as L-uncoupling. As a result, different electronic states are mixed. In addition, the spectrum was perturbed by interactions between s, p, and d states. Several electronic states and their perturbations had to be simulated together, before the calculated spectra started to show some similarity with the data. I regard the solution of this puzzle as one of the most challenging pieces of work I have done. Even before finishing my PhD I already knew that I would not stay in molecular spectroscopy. I either wanted to work in a more fundamental area of physics, or focus on an area which was directly related to the needs of society. Another option was going into industry, and I had several interviews and job offers. In the end, I decided to pursue applied research in a university setting, maintaining at least some of the freedom of academic research. I joined the group of Prof. J�rgen Wolfrum at the University of Heidelberg. There, I worked in physical chemistry, focusing on combustion diagnostics with lasers. Molecular spectroscopy, in which I was an expert by this time, was used to measure temperature and molecular concentrations in a flame. One of my main projects was carried out in collaboration with the Volkswagen company. We had to transport a truckload of lasers and equipment to an engine test stand at the plant and encountered problems such as soot on the windows of the transparent engine and optics dripping with oil coming from a Diesel engine. Changing fields was a crucial experience for me. Amazed to see how much of what I had learnt before could be applied within the new field, I realized that general skills are much more important than specific knowledge. I thought it would take a long time before I became productive in my new environment, but within months, graduate students who had been working in this area for much longer came and sought my advice and leadership. This experience gave me the self-confidence to venture into new areas, and provided the impetus for my later decision to come to the United States and start once again in a new field. When your work is directly related to cleaner and more efficient combustion, you can easily convince non-scientists of the relevance of your research. I enjoyed this, as well as the interactions with industry and engineers. However, I began to miss something, the quest for pure knowledge and the pursuit of goals which are only vaguely defined and change as the research progresses. I thus realized that my place would be in basic research. At 32 years, I decided to change fields once more. I wanted to switch to an area of fundamental physics where I could apply some of my knowledge in optics and spectroscopy and thus identified the field of cold atoms as the most promising area. At this time, my assessment was that the field of laser cooling and trapping had reached its peak, but there was still enough to be done. I didn't anticipate that the best was still to come. Leaving a long-term position in Germany and taking a short-term postdoc position in the U.S. was a risk for myself and my family. However, the time in Heidelberg in combustion research had helped me to discover what I really wanted to do, and also strengthened my self-confidence. I was willing to take risks which I wouldn't have taken a few years earlier. By talking to people and browsing through conference proceedings, I identified the leading groups in the field and sent out applications. I was pleased that I received two offers, despite my lack of experience with cold atoms. In the spring of 1990, I joined Dave Pritchard's group at MIT. During the first year at MIT, I was supported by a fellowship of DAAD (Deutscher Akademischer Auslandsdienst). It is a great tradition in Germany to support scientific study abroad, but unfortunately such a tradition does not exist in the U.S. Going abroad means more than just immersing yourself in a new culture. It also means that you free yourself from your previous environment and have the opportunity to change and redefine yourself. As a foreigner in a new area of research, I didn't feel bound to a certain tradition and could develop my own personal style - in lab work, giving talks, and discussions within the group. At MIT, where half of the graduate students are foreigners, there is no prejudice, but rather a tolerance and appreciation for unconventional ideas and styles of work. I also found a unique atmosphere in Dave Pritchard's group. Until then, I had worked in two rather large German groups. Dave's group was smaller, the interactions with him and within the group were very informal; and exciting science was pursued in an atmosphere of comradeship. Dave's knowledge of the field was enormous. During discussions, he could answer almost any question that came up, or immediately make an estimate whether a phenomenon was observable or not. Initially, I felt both intimidated and challenged by his scientific prowess, but soon we became more equal partners. This was the beginning of a wonderful collaboration that continues until the present day. Some account of it is given in the written version of my Nobel lecture. Towards the end of my PhD studies, in 1986, I married Gabriele Sauer, whom I had known since my high school years. We had three wonderful children, Jonas, born in 1986; Johanna in 1988; and Holger in 1992, who continue to surprise me with their developing talents and personalities; they enrich my life every day. My wife and I were very different and grew apart over the years. In 2001, we separated, two months before it was announced that I was awarded the Nobel prize. Despite some difficulties, the last year has been full of joy, and the Nobel ceremonies have added extra glamour, bringing together my family, friends and colleagues. It is those people to whom I am most grateful, and they have instilled in me a passion for life and a critical, but always optimistic perspective for the future.
Autobiography: Carl E. WiemanI was born on March 26, 1951 in the small town of Corvallis, Oregon. A number of years earlier my newly wed parents N. Orr and Alison Wieman, like somewhat belated pioneers, had driven their decrepit car across the country to settle deep in the forests of the Oregon coastal range. My father began working in the lumber industry and during most of my childhood he worked as a sawyer in a sawmill. I was the fourth of five children. Most of my childhood was spent in the woods of Oregon where lumber was the sole industry. Probably some of my spirit of independence came from growing up far from other houses and towns. The nearest tiny store was always many miles away over unpaved mountain roads. Some of my earliest childhood memories are of the long school bus rides that my siblings and I used to take over those winding roads to go to school. Much of my youth was spent wandering around in the forests of towering Douglas fir trees. I also spend much of my time reading and picking fruit and fir cones to earn spending money. Every Saturday my family would make a long expedition to the nearest town to do the week's worth of shopping. A stop at the public library was always part of these trips. Although I was unaware of it at the time, my parents must have made special arrangements for their children to use the library since we lived far outside the region it was supposed to serve. The librarians would also overlook the normal five-book limit and allow me to check out a large pile of books each week that I would then eagerly devour. That experience has left me with a profound appreciation for the value of public libraries. At the time I was quite envious that my friends had televisions while we did not, but in retrospect I am very grateful that I spent this time reading instead of watching TV. I went to primary school (up to grade 6) at Kings Valley grade school. It was a tiny rural school that had expanded from one to three rooms shortly before I enrolled. For the seventh grade I had to take the much longer bus ride (almost interminable for an impatient 13 year old!) to the small town of Philomath. My young idealistic teachers in mathematics and science there had a significant influence on me. I particularly remember my science teacher, Ron Tobias, who was just starting his first teaching job. I am sure that Philomath 7th grade, with all its children of loggers and farm workers, for whom education was not a particularly high priority, must have been a very tough job for a young teacher. At times I could sense hints of his frustration. However Mr. Tobias did a great deal to kindle my interest in science with his enthusiasm and knowledge. I still remember his explanations (far better than any of the material from my college courses!) of the structures of atoms in the periodic table and how these structures determined the various chemical properties and molecular reactions. After 7th grade my parents moved to Corvallis (home of Oregon State University) so that my siblings and I could both avoid the long bus rides and take advantage of the better school system offered by this "big city" of 25,000. It was a heady day for me when we moved into a house that had a central heating system instead of just a wood stove and had an actual paved street out front! Although I was never a very sociable child, Corvallis provided me with somewhat more comfortable companions. My intellectual interests and the liberal political attitudes of my parents were always somewhat at odds with the leanings most of my previous rural classmates, but I fit in better with the children of faculty at OSU. I became close friends with a very smart boy, Brook Firey, whose father Bill was a Professor of mathematics. One summer Bill gave Brook and I our own private course in geometry. It was a rewarding and eye-opening experience to get a glimpse of the richness of mathematics, even elementary geometry, as viewed by a true mathematician. And of course, at that age, I did not realize there was anything unusual about a University professor spending a few hours each day to provide personal instruction to two fourteen year olds. Brook and I also spent many hours engrossed in all sorts of projects constructing and investigating things. I think that much of my talent and enjoyment at improvising solutions to experimental problems goes back to those homebuilt projects. In this regard my older brother Howard also inspired me; he was always tinkering with machines and building astonishingly elaborate toys for his younger siblings. Carrying out these individual projects also developed in me a good sense of self-reliance and a sense when a piece of improvised apparatus was likely (or unlikely) to be adequate. This sense is one that I often see missing in students whose education has been confined to formal instruction. During high school I was a good student, but never quite at the top of the class. I mastered the material, but was usually a little too independent to do precisely what the teacher wanted, and so was never considered among the very best students. Usually the worse the teacher (at least according to me), the lower was my standing. Although always interested in science, my most memorable classes were in literature and writing. From 7th through 10th grade I was a passionate chess player, spending hours a day on it. I traveled all over Oregon and occasionally to nearby states to play in tournaments. I was highly ranked in the northwest US among my age group, but at the ripe old age of 16 decided to "retire" to spend my time in more productive activities. Those activities were studying and playing tennis. My high school grades, although not outstanding, were good enough to get me accepted into MIT. From what I now know about college admissions, I suspect my admission was considerably helped by their being intrigued to have a student who had spent much of his life literally in the wilds of Oregon. My accomplishments as a competitive chess and tennis player may also have helped. Although it may seem surprising that a boy from the woods of Oregon would aspire to go to MIT, my family always had a strong interest in education. Both my parents graduated from college and had come from welleducated families. My grandfather Henry Wieman was a rather well known Professor of Theology at the University of Chicago. Out my four siblings there are two Ph.D.'s, including a successful nuclear physicist, as well as a high-level software engineer. My tendency to intensely pursue a particular activity to the exclusion of everything else was and is one of my most notable strengths and weaknesses. After "retiring" from chess, my focus turned to tennis. That continued after I went to MIT, and I played intercollegiately my freshman year. I also learned to play squash rackets and took to it so naturally that I was quickly at the top of the freshman intercollegiate squash team. My squash career was notable in that I can claim to have lost to some of the best players in the country, including one future national champion. Unfortunately my rather fierce competitive drive exceeded my limited physical capacities, and after surviving several minor injuries caused by throwing myself into walls and such, by the end of my freshman year I had seriously damaged my right elbow from excessive practice at squash and tennis. After several unsuccessful treatments, I then switched to playing left handed, and by early in my second year of college was starting to again be competitive in both sports at the intercollegiate level. At that point I developed serious elbow problems in my left arm, and reluctantly came to the conclusion that at age 19, it was time for my second "retirement". It was only then I turned my full attention to physics. As one might imagine, going from the woods of Oregon to MIT was quite a culture shock. I did not do particularly well in classes my freshman year, but I greatly enjoyed an informal freshman seminar on physics that I had with Professor Al Hill. He was a gruff but kindly old faculty member. Although I had a general interest in physics at least since seventh grade, particularly the behavior of light and atoms, I was not totally convinced when I started at MIT that I wanted to go into physics. However, after this seminar and its casual far ranging discussions about physics, Al Hill encouraged me and suggested that I should get involved in research. I discussed this with my freshman advisor who was Daniel Kleppner, and he took me on to work in his laboratory my first summer of college. This was a dramatic change from my employment the previous summer. Then, just out of high school, I had worked in the lumber mill, "pulling on the green chain". As the green lumber came out of the mill on a large conveyor chain, my job was to pull it off and stack it in the appropriate pile. This was an exhausting job that gave me a clear taste of what real labor was like. Every now and then when I am fed up with some aspect of my job as an academic, it is useful to reflect on that summer on the green chain to remind myself how well off I am compared to all those people who spend their lives doing real work. I quickly became deeply engaged in research as an undergraduate and continued to work in Dan Kleppner's research group until I left for graduate school. I found this much more interesting and educational than taking courses, and quickly adopted a philosophy of taking as few courses as possible. Since I never did terribly well in most normal courses anyway, particularly ones that had exams, this worked out well. I was actually remarkably successful at avoiding courses, helped in large part by the events of the times. The last few weeks (and the dreaded final exams) of my freshman year were canceled because of massive protests over the Vietnam War, and during the following years there were many opportunities to participate in experiments in various sorts of alternatives to normal classes. I took full advantage of all of these alternatives, and their rather lax requirements and oversight. I also spent countless hours discussing physics with the graduate students and postdocs (notably Dave Pritchard) in Dan Kleppner's research group. My education as a physicist came largely from my work in Dan's lab and these interactions with him and his group. I also spent much time in physics discussions with an informal seminar group (the "physics family") run by Rai Weiss and Al Hill. In spite of (or because of) this unorthodox education, I ended up far more enthusiastic about physics than most of my classmates, as well as having a much better grasp of many basic concepts such as quantum mechanics. Of course I was considerably weaker in the formal solving of problems, and I still have not learned much of the standard material of the undergraduate curriculum. However, when I needed to know some material, I was completely comfortable with going out and learning it myself in a way that I discovered was not typical for my classmates. My undergraduate experience has always left me deeply suspicious of the claims of those who say a student cannot become a physicist without being required to take courses covering a whole list of specific topics. I have had a pretty successful career in optics and atomic physics without having a course in either, for example. Some may argue that this could only work because I was an extraordinary student, and the more typical student must be required to take a formal curriculum with a large number of courses and exams. However, it might be noted that before obtaining this unusual "education" there was little to indicate that I was anything special as a physics student. So one could equally well argue that it was not me that was exceptional, but rather the education I received. Perhaps if far more students learned physics in the haphazard way that I did, many more of them might turn out as motivated and successful as I have been. I did become extremely involved in research as an undergraduate. Through a chain of circumstances, helped out no doubt by my enthusiasm and willingness to put in long hours of work, I ended up with my own lab and my own experiment. This involved the construction and use of a tunable dye laser, which at that time was a very new and exciting device. This was the beginning of Kleppner's group moving into the use of lasers to study atomic physics. I spent my time blasting atoms with a dye laser tuned to the atomic resonance line and looking carefully at what happened. To a large extent much of my subsequent career has been variations on this basic theme. After spending many very late nights by myself taking data in the lab and showering every day at the athletic center after exercising, I started to wonder why I was paying all that money, of which I had little, to rent a dormitory room I almost never saw. So driven by my involvement in the research and a desire to save money, I actually moved into my lab. After about a half a year, living in the lab got pretty old, and so I moved into a normal apartment, but the story of my being so devoted to experimental physics that I actually lived in the lab has tended to follow me ever since. My work with dye lasers made me aware of the exciting developments in narrowband dye lasers and their applications to atomic spectroscopy being done by Ted H�nsch. That, along with the far superior weather and more relaxed academic atmosphere, convinced me to move from MIT to Stanford for graduate school. At Stanford I resisted the natural temptation to immediately jump into laser spectroscopy again, and so I spent a year looking fairly carefully into all of the different faculty and research areas in the department. However, in the end I concluded that working on laser spectroscopy with H�nsch was the best option. I began working with his group as they were developing a very high power narrowband dye laser for exciting the 1S-2S transition in hydrogen. Ted was a new enthusiastic young professor, the technology and the experiment were new and exciting, and because of my previous background I was able to become thoroughly involved in the experiment almost immediately. It was a fun time, made more so by the fact that we soon observed the H 1S-2S transition and used it to measure the Lamb shift of the 1S state. For my thesis work I then went on to develop the technique of polarization spectroscopy and built the first single mode continuous wave dye laser at 480 nm to further improve the 1S Lamb shift measurement and greatly improve the determination of the 1S-2S isotope shift. As I neared completion of my Ph.D., I became interested in the subject of parity violation in atoms. This was predicted by the theory of electroweak unification, but had not been seen. It seemed like the natural next step to my thesis work in that it was using precision spectroscopy of atoms to test fundamental physics. But rather than further test QED in atoms, which by then I was ready to accept as being confirmed as well as ever need be, the parity violation work was looking for new physics in atoms that went beyond QED and was far from certain. It offered the possibility of using atomic physics to do important elementary particle physics. I took a position as an assistant research scientist at University of Michigan to pursue these studies. I joined Bill Williams' ongoing experiment to measure this parity violation in atomic hydrogen using microwave spectroscopy. Shortly after I arrived at Michigan I found that the research scientist position I had taken was not the research faculty position that I had expected. It had all the disadvantages of a regular postdoc, but none of the advantages in that there was not sufficient research money in the grant to cover my salary, so that I had also had to teach, and I had to be responsible for much of the administration of the research group. However, I threw myself into the experiment and worked extremely hard, and my position was converted into a regular assistant professor position after a couple of years. Shortly after this I developed a somewhat different formulation for how to describe atomic parity violation experiments. This allowed me to see clearly how to compare the sensitivities of a large variety of different experimental approaches. At that same time I was also becoming increasingly disillusioned with the hydrogen experiment, and my new formulation made it clear to me that a quite different approach, using laser spectroscopy of cesium, would have a far better chance of success. For a variety of reasons I chose to pursue the cesium experiment on my own, after first receiving assurances from the department chair that this was a suitable activity. Unfortunately, my abandoning of the hydrogen experiment to pursue my own atomic parity violation experiment lead to considerable friction with senior faculty and general strife within the department. As a young assistant professor na�ve in departmental politics I was quite vulnerable, and had a difficult time during my subsequent years at Michigan. However, during that time, Sarah Gilbert and I were able to get funding from Research Corporation and then NSF and used it to thoroughly develop a novel experimental approach for measuring atomic PV in cesium. Sarah was a graduate student that I had met soon after I arrived at Michigan. We then worked intensively with graduate students Rich Watts and Charlie Noecker to implement this difficult experiment. By 1984 we had made sufficient progress to indicate the viability of our approach, and this attracted an offer of a faculty position at the University of Colorado in Boulder. I eagerly accepted the offer. The year 1984 was a very active one for me. First, Sarah Gilbert completed her Ph.D., and I accepted the job at Colorado. In late August we then packed up the entire lab into the back of a rental truck along with all the personal furniture of the graduate students, and then Sarah, Rich, Charlie, Charlie's girlfriend, and I set out on a modern day pioneer caravan across the Great Plains to Boulder, Colorado. After quickly unpacking the truck, Sarah and I then left to fly out to Oregon for our wedding. We had been anticipating this since shortly after we met, but we had delayed until after Sarah finished her degree. We then returned to Boulder to start our new jobs and a new lab. In the supportive environment of JILA and the Department of Physics in Boulder, along with lots of very hard work, the four of us, Sarah, Rich, Charlie, and myself, were able to make rapid progress and in less than a year completed our first measurement of parity violation in cesium. As with all my experiments, I had started out wildly optimistic as to the difficulty and time required for this experiment, and it was both a tremendous relief and a tremendous satisfaction when it succeeded. It was the best measurement of atomic parity violation at a time when this subject was being pursued by a number of notable atomic physics groups. Our result established both to myself and the rest of the world that I would have a career as research physicist; something that had sunk into considerable doubt during my seven years of meager accomplishments at Michigan. Shortly after the success of the PV experiment I was given tenure and promoted to Full Professor at Colorado. During the subsequent 15 years, my group has carried out two further generations of this long and difficulty experiment with ever improving accuracy. I would be remiss if I failed to mention the tremendous benefits that I have gained in my career by having a wife who is a very talented and intelligent physicist (as well as being a wonderful person of course). Shortly after we arrived in Boulder, Sarah took a job at the NIST Boulder labs where she has worked ever since. We worked together on the PV experiments, and still collaborate on an occasional small project. Talking with Sarah about physics has always provided me with countless inspirations for new ideas, and has revealed critical flaws that I had overlooked in twice as many bad ideas. She also can understand and share in my obsession with the research and its occasional extraordinary demands. Finally, her ruthless editing has greatly improved the writing of nearly all of my papers. When we are not working, Sarah and I can usually be found running or hiking on the trails of the Boulder Mountain Parks. We can also occasionally (but not frequently enough) be found at our house on the central Oregon coast. The development of the diode laser technology that was needed for the third generation of the parity violation experiment led to my involvement with laser cooling and trapping and ultimately BEC. Originally in about 1984 Rich Watts and I were simply looking for something fun and easy to do with the diode laser technology we had developed for the PV experiment, as a respite from the very long hard grind of that project. This resulted in our slowing atoms using lasers that were about 1% of the cost of what was used for previous work by Hall and Phillips. I then became increasingly interested in laser cooling and trapping. Initially my work on it focused largely on developing it as a useful technology for doing other atomic physics, but then I became more involved in studying the novel behavior of atoms at the unprecedented temperatures we could achieve. In the process of those studies I worked with an undergraduate Bill Swann to invent the vapor-cell MOT to replace the traditional atomic beam loading of optical traps. This provided a means to trap atoms using only inexpensive diode lasers and a small glass cell, which was a dramatic advance towards making laser trapping a simple and widely useable technology. To me personally, this reduction in the cost and complication offered the opportunity to explore a variety of speculative directions involving laser cooled atoms with relatively little risk, since the cost and effort was now quite modest. One such quick experiment was to switch the laser cooled and trapped atoms to a magnetic trap in order to avoid the limits we had discovered were imposed by the photons in the optical trap. This worked so easily and so well - we obtained trapped atoms about 100 times colder than had been achieved previously, with a corresponding enhancement in phase space density - that it inspired me to pursue goals grander than just better trapping and cooling technology; namely, the attainment of BEC by further cooling in the magnetic trap. Fortunately Eric Cornell joined me at just that time (1990) to pursue the goal of BEC. Ours turned out to be an extraordinarily friendly and effective partnership that has continued up to the present. Our pursuit of BEC is now well-documented history. Over the past several years I have become increasingly involved with trying to improve undergraduate physics education and have been balancing my time between that and my research. I have been examining alternative curricula and learning about the research in physics education as to how students do and do not learn. A particular concern has been improving how physics is taught to students who are not planning to become physicists, in the hope of one day making physics understandable, useful, and interesting to a large fraction of the population. My efforts have ranged from working with national organizations pursuing widespread change in undergraduate physics education to developing useful innovations in the individual courses that I teach. Because of my particular concerns, these courses have lately been large introductory courses primarily for nonscience students.
Nobel Lecture: Eric A. CornellBose-Einstein Condensation in a Dilute Gas; The First 70 Years and Some Recent ExperimentsPresentation 1 min.
39 min.
Nobel Lecture: Wolfgang KetterleWhen Atoms Behave as Waves: Bose-Einstein Condensation and the Atom LaserPresentation 1 min.
40 min.
Nobel Lecture: Carl E. WiemanBose-Einstein Condensation in a Dilute Gas; The First 70 Years and Some Recent ExperimentsPresentation 1 min.
38 min. Source: http://nobelprize.org/nobel_prizes/physics/laureates/2001/index.html
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