This was the first technical problem in theoretical physics I had ever tackled in my life, and I approached it from a very elementary point of view. I read papers on statistical mechanics, on properties of the radiation field, and started working with rather naive and common-sense kinematic pictures. I tried some arithmetic and obtained a formula much like Teller's, but with a numerical factor of about four in front as the rate of transfer. It was a messy little job. Edward was not satisfied with my rather elementary derivations.
Shortly after I had discussed this work with Teller, a young, more professional mathematical physicist, Henry Hurwitz, Jr., joined Teller's group and with his much better mathematical techniques and experience in the special functions that were used in this type of problem, he obtained a formula, much more scholarly than mine, involving Bessel functions. Indeed, the exact numerical factor was not very different from four. If I remember correctly, it was a root of a certain Bessel function.
The idea was to have some thermonuclear material — deuterium — next to the fission bomb, and to let it ignite after the uranium bomb had exploded. How to do it in detail was the big problem, and it was by no means easy to see how such an arrangement would ignite and not just sputter and fizzle out. There was also, theoretically at least, the hazard of getting more of an explosion than intended and of having the whole atmosphere of the earth ignite! The well-known physicist Gregory Breit was involved in calculating the chances of the ignition of the atmosphere. These, of course, had to be zero before one could even think of tampering with thermonuclear reactions on earth.
I think it was Bethe, with Emil Konopinski, a well-known theoretical physicist, who suggested tritium instead of deuterium as a material easier to ignite, given the temperature of the fission bomb. Such an engineering suggestion from theoretical work came from his superb knowledge of theoretical nuclear physics.
Bethe was the head of the theoretical division, as it was called. Actually it was his and Robert F. Bacher's papers in Reviews of Modern Physics which were used as the "bible" of the Los Alamos scientists, for they contained the bulk of the theoretical ideas and experimental facts known at the time. Bethe, now a Nobel Prize-winner for his earlier discovery of the mechanism of energy generation in the sun and other stars (the so-called carbon cycle), is, among other things, a virtuoso in the techniques of mathematical physics. As Feynman once put it, at Los Alamos he was, with his rigorous and definitive work, like a battleship moving steadily forward, surrounded by a flotilla of smaller vessels, the younger theoretical workers of the laboratory. He is one of the few persons for whom I merely had respect in the beginning but over the years have continuously developed liking and admiration.
When I first met Teller, he appeared youthful, always intense, visibly ambitious, and harboring a smoldering passion for achievement in physics. He was a warm person and clearly desired friendship with other physicists. Possessing a very critical mind, he also showed quickness, sense, and great determination and persistence. However, I think he also showed less feeling for true simplicity in the more fundamental levels of theoretical physics. To exaggerate a bit, I would say his talents were more in the direction of engineering, construction, and the surveying of existing methods. But undoubtedly he also had great ingenuity.
Teller was well known for his work on molecules, but he may have considered this as a sort of secondary field. I think it was the ease with which Gamow had new ideas without any technical arsenal at his disposal that pushed Teller into trying to emulate him and to attempt more fundamental work.
After he got into personal difficulties with Teller on the organizational features of the hydrogen work, Gamow later told me that before the war Teller was, in his view, a different person — helpful, willing, and able to work on other people's ideas without insisting on everything having to be his own. According to Gamow, something changed in him after he joined the Los Alamos Project.
Of course, many physicists who were almost congenitally ivory-tower types got their heads turned with the sudden realization of not only the practical but worldwide historical importance of their work — not to mention the more trivial but obvious matter of the enormous sums of money and physical facilities that surpassed anything in their previous experience. Perhaps this played a role in the personality change of some principals; with Oppenheimer, the director, it may have had a bearing on his subsequent activities, career, ideas, and role as a universal sage. Like Teller, Oppenheimer may have had a feeling of inadequacy as compared with the creators of great new physical theories. He was equal to or even more brilliant and quick than Teller, but perhaps lacked the ultimate creative spark of originality. With his fantastic intelligence, he must have realized this himself. In speed of understanding and in critical ability, he probably surpassed Bethe or Fermi.
Teller wanted to have his own stamp on much of the essential work of Los Alamos, at first via his own approach to the fission bomb. He was pushing for milder explosions, dilution of material, etc. In spite of calculations by Konopinski and others that gave a poor outlook for some of these plans, he was trying by every means to have his own adopted. Collaboration with Bethe, who was head of the theoretical division, became increasingly difficult.
As disagreements between Teller and Bethe became more frequent and acute, Teller threatened to leave. Oppenheimer, who did not want to lose such a brilliant scientist, agreed to let him and his group work in a more future-oriented field, independent of the project's main line. This is how Teller began to concentrate and organize the theoretical work for the "Super." Konopinski, Weisskopf, Serber, Richard Feynman, William Rarita, and many others all had special contributions to make, but it was really Teller who kept the thing together and moving forward during the war.
After Fermi's arrival, Teller's group became a part of Fermi's division. Fermi took great interest in the theoretical work on the thermonuclear reactions and H-bomb possibilities; at the end of the war he gave a series of lectures magnificently summarizing the work done until then — thanks mostly to the investigations of Teller and his group.
But even then, before the success of the atomic bomb itself, some of Teller's actions gave clues to what led to much of the unpleasantness and waste of time in the so-called H-Bomb controversy.
Teller's group was composed of a number of very interesting young physicists, younger even than Teller, Konopinski, or myself. It included Nick Metropolis, a Greek-American with a wonderful personality; Harold and Mary Argo, a husband-and-wife team, eager and talented; Jane Roeberg, a young woman who gave the impression of being competent; and a few others whose names I do not now remember.
There was, of course, much contact with other groups of physicists who were on the borderline of problems concerning the possibilities of a "super"; discussions with them were frequent, pleasant, and concerned many different branches of physics. One could hear about the pros and cons of the idea of implosion, which was new and vigorously debated in many of the offices. These discussions were completely open. Nothing was concealed from anybody who was a scientist.
The more formal way of letting people know what was going on was the weekly colloquia, which were held in a big hangar that also served as the movie theater. These talks covered progress of the work of the whole laboratory and the specific problems which the project encountered. They were run by Oppenheimer himself.