The First 35 Years of the Aspen Center for Physics

by Jeremy Bernstein

Chapter II: A Start

Stranahan got his PhD in the fall of 1961. He had an appointment as a research associate at Purdue University. It had become clear that Aspen was going to be a permanent part of his life so he used some of his inheritance to lay down roots. He bought sixty acres of land in nearby Woody Creek for $35,000 and he built a very large log home with a magnificent view of the mountains for $25,000. He had raised or supplied enough money for a physics building. It was time to begin building it. Stranahan had become friendly with a local architect and had assumed that he would have his choice of architects. But the Aspen Institute owned the land on which the Physics Center was going to be located. Indeed the Center was the Physics Division of the Aspen Institute, which meant that they did all the bookkeeping and had the non–profit status. It also meant that they owned whatever building would be constructed even if Stranahan's money had helped to make it possible. Hence it was they who would choose the architect and not Stranahan. They insisted on choosing Herbert Bayer who had designed the buildings on the rest of the campus. Bayer, who had a very important influence on the architectural look of Aspen, had an interesting curriculum vitae.

Herbert Bayer, Architect

Bayer was born in Austria in 1900. After studying and working with various artists in Germany and Austria he joined Walter Gropius's Bauhaus where he studied with people like Wassily Kandinsky. He then became the director of printing and advertising at the Bauhaus. In 1928 he became the art director of the German Vogue. He remained in Germany even after people like Gropius had left, and he even designed a brochure for the 1936 Berlin Olympic games. But in 1937 his work was designated as “degenerate art” and the next year he left for New York. In 1946 Walter Paepcke hired him to come to Aspen and plan the renewal of the town. One thing that he did was to participate in the renovation of the Wheeler Opera House. This was a magnificent structure that had been built in 1889 at the height of the silver boom. Like much in the town it had fallen into disrepair during the “Quiet Years” after the price of silver had collapsed and before Walter Paepcke decided to rejuvenate the town.

Now Bayer was to design the building for the Physics Center. Bayer brought back a Bauhaus design to be made out of handmade stone–block structures with a bid of $225,000–vastly more than any money that had or could be raised. The Institute instructed Bayer to build it out of cement blocks. It was not going to be ready until the middle of the summer. In the meanwhile Craig supplied office space at the Institute. Stranahan had given the design of the building a good deal of thought. He had decided that the physicists should be paired up two to an office. There would be no students. A good collaborative arrangement among theoretical physicists is usually in twos. There would be ten offices or a total of twenty physicists. There would be a small common room which would house the library, Stranahan bought all the books and the subscriptions to a few journals like the Physical Review. There were, Stranahan decided, not going to be any seminars. People would stay in their offices and work. As the summer evolved the physicists decided that they needed seminars so chairs were set up in the common room.

The First Year: 1962

At the entrance there was a desk for a receptionist. The choice that summer, Elizabeth Baldwin, was hired by Craig. Since she had worked in a bank she was known as “Betsy Bank.” Stranahan recalled that she was “young and cheerful and tolerant.” In dealing with physicists the latter was important. The business model, if you can call it that, was very different from the rest of the Institute. The Institute catered to wealthy businessmen who could afford to spend a high tuition to enhance their cultural dimension. They would live on the Institute campus where there was also a restaurant. It was 1.4 miles from the center of town near a river. From time to time they might frequent one of the local restaurants such as the Copper Kettle or the Golden Horn which had national reputations. There was a shuttle to take Institute people into town. The physicists on the other hand, Stranahan excepted, were living on modest academic salaries. They needed accommodations in town rented from the locals. One of Betsy Bank's jobs was to find reasonably priced rentals. Here she could collaborate with the Aspen Music Festival and School which Walter Paepcke also helped to found in 1949. The musicians and their students also needed rentals in town so Betsy Bank was able to collaborate.

The physicists would not receive any money from the Center. What made the visit possible financially for most of them was what was known as the “summer salary,” While one received checks from one's university every month, the appointments were usually for the academic year which did not include June, July and August. If one had a government grant from say the National Science Foundation, some of this could be used to pay oneself for at least part of the summer months–if one used that time to do the research for which the grant was intended. Stranahan felt that the physicists who would be accepted to come to Aspen would have grants and summer salaries. There was, as one might imagine, no shuttle to town. Quite soon there were free bicycles the physicists could borrow for the commute. There was little reason to have a car unless one was going to hike or climb somewhere out of town. The physicists brown–bagged their lunches at the Center. The Center got a grant from the Office of Naval Research for $15,000 of which fifteen percent went to the Institute for overhead. It was used to pay things like Betsy Bank's salary and the electricity and water.

That first summer there were forty–one physicists staggered in different time periods from June through August. (See the appendix to this chapter for the list.) The building became available in mid–summer. The list of physicists from that summer is quite interesting. They came from all over the country and from many different universities. There was even one from Varian Associates, a California company that was involved with electromagnetic equipment. A few listed their “specialization.” Most of these were in high energy or elementary particle physics. This was the hot subject of the day. The plethora of recently discovered particles was beginning to fit into fascinating mathematical patterns. To a theoretical physicist this was irresistible. There are two women on the list, both wives of attending physicists, although Fay Selove, Walter Selove's wife, was a distinguished physicist in her own right. A remarkable letter of invitation had been sent out under the signatures of Baranger, Cohen, Stranahan and Lincoln Wolfenstein–Baranger and Wolfenstein were both from Carnegie Tech. The letter, reproduced in the appendix, describes the nascent organization. It even suggests that the larger accommodations should cost about $125 a month! It is cautious about making too much of a public announcement since the facilities were going to be limited and gives a short list of distinguished physicists who have already agreed to come.

Hans Bethe

One of the early visitors was Hans Bethe. He came officially for the first time in 1965. He was one of the most distinguished theoretical physicists of the twentieth century. He made very important contributions in every branch of physics and because of his Los Alamos experience had become a spokesman for the control of nuclear weapons. His presence at the Center lent a gravitas to the place. His effect on the Center was so significant that I am going the present a profile of his life.

Bethe was born on July 2,1906 in Strasbourg which was then part of Germany. For a biography, see my Hans Bethe, Prophet of Energy, Basic Books, New York, 1980, the pages of which are cited below. His father was a Protestant physiologist at the university. His mother, who was Jewish, also came from a medical family. Bethe showed mathematical skills at a very early age. By the time he was fourteen he had taught himself the calculus from a book his father had. By this time the family had moved to Frankfurt and in 1924 Bethe entered the university there. From the point of view of physics the curriculum was rather limited and one of his professors told Bethe that he had to go to Munich to study with Arnold Sommerfeld. Not only was Sommerfeld an outstanding theoretical physicist but he was one of the truly great physics teachers. The number of his students such as Werner Heisenberg and Wolfgang Pauli who went on to win the Nobel Prize was legion. Bethe had a couple of letters of recommendation and Sommerfeld said to him, “All right, you are very young, but come to my seminar.” [Hans Bethe, p. 14]. Bethe described the scene, “Sommerfeld had a huge office lined with books, and next to it was an equally huge office for his official assistant. And then there was another room of just about the same size which was simultaneously the library and the abode of everybody else. All the foreign postdoctorals and the German graduate students–eight or ten of us–sat in that room. There was an enormously long table, and we sat at that table as best we could. Later on, when I went back after my doctor's degree [Hans Bethe, p. 14] on a fellowship, I got a desk in a separate room. But what a room! Most of it was occupied by a spiral staircase leading to the basement. There was just enough space for a desk and for people to pass when they went up and down the staircase which they did all day long.” [Hans Bethe, p. 14]

Sommerfeld gave an advanced course and then there was the seminar. It was once a week for two–and–a–half hours. Bethe said that Sommerfeld would occasionally interrupt with what sounded like a stupid question. The question usually went to the heart of the matter and frequently revealed that the speaker had not understood the problem he was dealing with, in which case Sommerfeld would explain it to him. Because of his eminence, Sommerfeld got preprints of the important papers in theoretical physics and in 1926 he got Schrödinger's papers on wave mechanics. This gave Bethe the opportunity to learn the theory from its inception. He wrote his thesis on X–ray interactions with crystals and got his degree in 1928 and then had to look for a job. Sommerfeld had left for a sabbatical trip around the world and could not help. Jobs were very scarce and many PhD's went into high school teaching. Bethe recalled that the job situation in Germany [Hans Bethe, p. 14] was as bad in 1928 as when he came to the United States in 1935 in the midst of the Great Depression. But Bethe did get a small job at the University of Frankfurt and then he got an offer to be the research assistant of P.P. Ewald in Stuttgart, a noted crystallographer who had read Bethe's thesis. Bethe told me, “I was considered a child of the family. They invited me very often for dinner. They invited me to go on walks with them on Sunday, and if they didn't feel like going themselves they asked me to take the two older children–a boy fourteen and a girl twelve–for walks by myself, which was also very nice. The girl, Rose, later became my wife, so I really did become one of the family. The arrangement back in 1929 was a very happy one, and especially happy for me because my parents had been divorced two years before.” [Hans Bethe, p. 23] One of Bethe's “duties” was to give a course on the new quantum mechanics to Ewald and all the young assistants in the physics department. This happy arrangement came to an end when Sommerfeld returned from his trip and demanded Bethe back. That is when he got his own room.

By 1928 Bethe found that things were beginning to go wrong in Germany. Many of the young people he talked to at the university were fixated [Hans Bethe, p. 23] on the injustice of the Treaty of Versailles which ended the First Word War and spoke about the renaissance of an imperial Germany. There were even a few physics students in the nascent Nazi movement. Bethe was happy to get to Rome on a Rockefeller Foundation fellowship after a time in Cambridge University. The physics in Rome was dominated by Enrico Fermi who seemed to Bethe to be like the bright Italian sunshine. They wrote a paper together after two day's research which Fermi typed himself. Bethe told me that Fermi taught him how to write a scientific paper simply and clearly. In 1931 Bethe returned to Germany which was in a state of deep depression with banks failing and the like. But Bethe did not then think that the Nazis would take over. One of the physicists who came to work with Sommerfeld at that time was Lloyd Smith from Cornell, a connection that in a few years became very important to Bethe. In early 1933 Hitler took over Germany and the first racial laws were promulgated. Bethe was on a ski trip to Austria and when he got back, one of his students told him that a list of people who had been fired from the university in Munich because they had some Jewish ancestry, had been published in the newspaper. This way did Bethe learn that he had lost his job. Sommerfeld immediately set out to find jobs for his Jewish students in Germany but to Bethe it became clear that he had to leave the country. Fortunately he was offered a job at the University of Manchester, but in 1934 he got a cable from Cornell offering him an acting assistant professorship which paid $3,000 a year. Bethe went and despite offers from almost all the leading universities, never left.

When the war broke out Bethe was not yet an American citizen so he could not get clearance to work on any of the classified military projects, so he made one up. He worked on the penetration of armor by projectiles. The paper he wrote became a classic in that field. It was classified which meant that Bethe could not read it until later after he became a citizen in 1941 and had his clearance to work on the atomic bomb. In the late 1930's Bethe wrote two monumental review articles on everything that was then known about nuclear physics. They became known as “Bethe's Bible.” In March of 1941 Bethe received a phone call from Robert Oppenheimer in which, in a coded way, Oppenheimer managed to convey the fact that he was organizing a small group at Berkeley to consider the possibilities of making nuclear weapons. On the way to Berkeley, Bethe stopped in Chicago and saw enough of Fermi's work on the first nuclear reactor to become persuaded that nuclear weapons were a real possibility. Edward Teller was then in Chicago and the two of them went west by train. In a private compartment they discussed the possibility of making a hydrogen bomb, a discussion that continued throughout their stay in Berkeley and even on walks in Yosemite. In the spring of 1943 Los Alamos was created and Oppenheimer made Bethe the head of the theory division. One of its members was the young Feynman who had just gotten his PhD from Princeton. His arguments with Bethe became legendary. Bethe kept Feynman in his place because Bethe was better in mental arithmetic and other such calculations. Bethe could carry out an entire physics calculation in his head. When the war was over Bethe persuaded Feynman to come to Cornell where he made his great contributions to quantum electrodynamics.

While Bethe was never a technical climber he was a great mountain walker. He had discovered Aspen a few years before the Physics Center was created and had come on vacation to walk in the mountains and to listen to the music. It was natural for him to come to the new Center as a participant. When Bethe won the Nobel Prize in 1967 for his work on stellar energy he gave a portion to the Center for the construction of a new building which is now named for him. He died on March 6, 2005. Stranahan recalls that Betsy Bank came to him during Bethe's first summer in a state of near panic. Bethe wanted to dictate a letter to her and she had no idea how to do that. Stranahan told her to fake it and apparently that worked. Stranahan was quite content with the Center's symbiotic relationship with the Institute. People like Bethe participated in the Institute seminars which was certainly a good thing. It might have continued like that for some time except that in 1965, Craig was forced out. The new direction of the Institute could not see why they needed a Physics Division and indeed why their building could not be better used. There was a real possibility that the Center would close.

It is an interesting list. There is a wide distribution of institutions but only one from industry, Arden Sher from Varian. There are no participants from European institutions although one recognizes people like Bethe and Kurt Symanzik who were originally from Germany. Symanzik was one of the most distinguished mathematical physicists of his generation. Indeed, the list is full of distinguished physicists. It is noticeable that there are almost no women and no racial minorities. This reflected the state of the field at that time. In the next years this would change dramatically. Most of the physicists on the list would have described themselves as elementary particle or high–energy physicists. There were a few condensed–matter specialists but no astrophysicists except for Bethe who was a polymath, and certainly no bio–physicists. That also changed. The Center would soon attract people from industrial laboratories like IBM and Bell Labs, and there would be many more from government laboratories like Los Alamos. The 1962 list is short. A current list includes over 1,000 physicists visiting annually in summer and winter.
Chapter III