I devote this chapter to things that Teller and Ulam later said about the critical 1951 ideas that led to the successful H bomb.
When Teller was anointed Father of the H Bomb following the successful thermonuclear test in late 1952, he did not back away from the name, for indeed he thought he deserved it. Yet at the same time he was embarrassed, for many of his colleagues did not appreciate the searchlight of fame being focused on a single person.[10] So he graciously wrote a lengthy article to share the credit, “The Work of Many People.”{4} In that article he cites Ulam’s “disquieting,” then “discouraging” calculations on the classical Super. Regarding new ideas and eventual success with the equilibrium Super, he credits Ulam with “an imaginative suggestion”—a modest accolade that he later called a “white lie” to soothe ruffled feathers.{5} Then he goes on:
Even before the Greenhouse test [in May 1951] it became evident to a small group of people in Los Alamos that a thermonuclear bomb might be constructed in a comparatively easy manner. To many who were not closely connected to our work, this has appeared as a particularly unexpected and ingenious development. In actual fact this too was the result of hard work and hard thought by many people. The thoughts were incomplete, but all the fruitful elements were present, and it was clearly a question of only a short period until the ideas and suggestions were to crystallize into something concrete and provable.
Oh, Edward, your human frailty is so much on display. Despite the rich scattering of names in the rest of this “many people” article (more than forty, including mine), no names appear in this paragraph.
One of the people who regarded the Teller-Ulam idea as unexpected and ingenious was the eminent theoretical physicist Hans Bethe, who called this breakthrough “an entirely unexpected departure from the previous development.”{6} Bethe said also, “In January 1951, Teller obviously did not know how to save the thermonuclear program.”{7} Although not employed full-time at Los Alamos in early 1951, Bethe was no doubt fully informed. He had headed the Theoretical Division at Los Alamos during the war years and remained a valued consultant. He was known for the care with which he chose his words.
A few years later, in his book The Legacy of Hiroshima, Teller presents a similar account, with Ulam still factored out and Freddie de Hoffmann factored in:{8}
I approached the problem by attempting to free myself entirely from our original concept. That done, it soon became obvious that the job could be done in other ways. During the urgent computations for Greenhouse [scheduled for May 1951], many of the hard-working physicists had participated in offhand discussions about the bomb’s final design. Some of these ideas were fantastic. Some were practical. None were fully examined. They had been shoved aside by the vital need to complete the calculations for the test. With the theoretical work on Greenhouse finished, these weapons ideas could be examined in detail. Eager and anxious to come to grips with the real problem, our group at Los Alamos devoted its full attention to ways of constructing an actual bomb.
About February 1, 1951, I suggested a possible approach to the problem. Frederic de Hoffmann, acting on the suggestion, made a fine calculation and projection of the idea.
This was a little too much for Stan Ulam. Although he made no public protestation, he wrote a letter to Glenn Seaborg, Chairman of the Atomic Energy Commission, on March 16, 1962, objecting to Teller’s version of events.{9}
…the history of the new “idea” leading to the present class of designs is as follows: One day early in January in 1951 [in fact almost surely February] it occurred to me that one should employ an implosion of the main body of the device and thus obtain very high compressions of the thermonuclear part, which then might be made to give a considerable energy yield. I mentioned this possibility, with a sketch of a scheme how to construct it, to Dr. Bradbury one morning. The next day I communicated it to Edward, who by that time was convinced that the old scheme [the classical Super] might not work. For the first half an hour or so during our conversation, he did not want to accept this new possibility but in the subsequent discussion, he took to it very eagerly. In subsequent discussions we have devised certain arrangements which appear in a report written jointly by us.
It is therefore perhaps with some surprise that I noticed in the above-mentioned book [The Legacy of Hiroshima] a presentation of this little history stating something as follows: “I have communicated my idea to deHoffmann [sic] who calculated… etc”. In fact the joint report by deHoffmann and Teller [written by de Hoffmann and, at his initiative, signed only by Teller] is subsequent to the report 1225 by myself and Edward and it mentions explicitly the origin of the two-stage scheme and makes use of this previous report.
In his later published version of these events, Ulam is more circumspect. He was apparently worried about the possibility of inadvertently revealing classified information. Here is some of what he had to say:{10}
Perhaps a change [in the outlook for the Super] came with a proposal I contributed. I thought of a way to modify the whole approach by injecting a repetition of certain arrangements. Unfortunately, the idea or set of ideas involved is still classified and cannot be described here.
…
Shortly after responding [to Associate lab director Darol Froman in late January 1951] I thought of an iterative scheme. After I put my thoughts in order and made a semi-concrete sketch, I went to Carson Mark to discuss it… The same afternoon, I went to see Norris Bradbury[11] and mentioned this scheme. He quickly grasped its possibilities and at once showed great interest in pursuing it. The next morning, I spoke to Teller. I don’t think he had any real animosity toward me for the negative results of the work with Everett[12] so damaging to his plans, but our relationship seemed definitely strained. At once, Edward took up my suggestions, hesitantly at first, but enthusiastically after a few hours. He had seen not only the novel elements, but had found a parallel version, an alternative to what I had said perhaps more convenient and generalized… In the following days I saw Edward several times. We discussed the problem for about half an hour each time. I wrote a first sketch of the proposal. Teller made some changes and additions, and we wrote a joint report quickly. It contained the first engineering sketches of the new possibilities of starting thermonuclear explosions. We wrote about two parallel schemes based on these principles. The report became the fundamental basis for the design of the first successful thermonuclear reactions and the test in the Pacific called “Mike.”… A more detailed follow-up report was written by Teller and de Hoffmann.
10
Teller was singled out for credit especially by James Shepley and Clay Blair, Jr. in their book
11
Bradbury, the director of the laboratory, was informal and approachable. Ulam, or just about anyone else, could drop in on him with little fanfare and little advance notice. Bradbury, like Mark, understood in detail the work that was going on at the lab.
12
Cornelius Everett, the other half of Ulam’s two-person group in the Theoretical Division, was as retiring as Ulam was gregarious. When going from one place to another in the lab, Everett had the habit of walking close to the side of a corridor, tapping the wall with one hand to guide his progress, so that his thoughts could be elsewhere. He was known for the meticulous accuracy of his work. He and Ulam carried out the calculations that cast doubt on the feasibility of the classical Super.