In October 1943, he received an invitation from Hans Bethe to join the Manhattan Project at the secret Los Alamos Laboratory in New Mexico. There, he worked on the hydrodynamic calculations to predict the behavior of the explosive lenses that were needed by an implosion-type weapon. He was assigned to Edward Teller’s group, where he worked on Teller’s “Super” bomb for Teller and Enrico Fermi. After the war he left to become an associate professor at the University of Southern California, but returned to Los Alamos in 1946 to work on thermonuclear weapons. With the aid of a cadre of female “computers”, including his wife Françoise Aron Ulam, he found that Teller’s “Super” design was unworkable. In January 1951, Ulam and Teller came up with the Teller–Ulam design, which is the basis for all thermonuclear weapons.
In January 1951, Ulam had another idea: to channel the mechanical shock of a nuclear explosion so as to compress the fusion fuel. On the recommendation of his wife, Ulam discussed this idea with Bradbury and Mark before he told Teller about it. Almost immediately, Teller saw its merit, but noted that soft X-rays from the fission bomb would compress the thermonuclear fuel more strongly than mechanical shock and suggested ways to enhance this effect. On 9 March 1951, Teller and Ulam submitted a joint report describing these innovations. A few weeks later, Teller suggested placing a fissile rod or cylinder at the center of the fusion fuel. The detonation of this “spark plug” would help to initiate and enhance the fusion reaction. The design based on these ideas, called staged radiation implosion, has become the standard way to build thermonuclear weapons. It is often described as the “Teller–Ulam design”.
In September 1951, after a series of differences with Bradbury and other scientists, Teller resigned from Los Alamos, and returned to the University of Chicago. At about the same time, Ulam went on leave as a visiting professor at Harvard for a semester. Although Teller and Ulam submitted a joint report on their design and jointly applied for a patent on it, they soon became involved in a dispute over who deserved credit. After the war, Bethe returned to Cornell University, but he was deeply involved in the development of thermonuclear weapons as a consultant. In 1954, he wrote an article on the history of the H-bomb, which presents his opinion that both men contributed very significantly to the breakthrough. This balanced view is shared by others who were involved, including Mark and Fermi, but Teller persistently attempted to downplay Ulam’s role. “After the H-bomb was made,” Bethe recalled, “reporters started to call Teller the father of the H-bomb. For the sake of history, I think it is more precise to say that Ulam is the father, because he provided the seed, and Teller is the mother, because he remained with the child. As for me, I guess I am the midwife.”
A copious plate of pasta arrived, with no sauce. Teller suddenly stabbed his palms with a fork and rummaged through the strands of linguine. When a bright red river surged from beneath the plain pasta, Teller stood up, dripping red palms outstretched. Voila! The thrillingly gruesome “Linguine a la Stigmata.” Waiters smiled, diners at nearby tables didn’t notice a thing, and the linguine was served to one and all.
To advocate an aggressive development program, Ernest Lawrence and Luis Alvarez came to Los Alamos, where they conferred with Norris Bradbury, the laboratory director, and with George Gamow, Edward Teller, and Ulam. Soon, these three became members of a short-lived committee appointed by Bradbury to study the problem, with Teller as chairman. At this time, research on the use of a fission weapon to create a fusion reaction had been ongoing since 1942, but the design was still essentially the one originally proposed by Teller. His concept was to put tritium and/or deuterium in close proximity to a fission bomb, with the hope that the heat and intense flux of neutrons released when the bomb exploded, would ignite a self-sustaining fusion reaction. Reactions of these isotopes of hydrogen are of interest because the energy per unit mass of fuel released by their fusion is much larger than that from fission of heavy nuclei.
Because the results of calculations based on Teller’s concept were discouraging, many scientists believed it could not lead to a successful weapon, while others had moral and economic grounds for not proceeding. Consequently, several senior people of the Manhattan Project opposed development, including Bethe and Oppenheimer. To clarify the situation, Ulam and von Neumann resolved to do new calculations to determine whether Teller’s approach was feasible. To carry out these studies, von Neumann decided to use electronic computers: ENIAC at Aberdeen, a new computer, MANIAC, at Princeton, and its twin, which was under construction at Los Alamos. Ulam enlisted Everett to follow a completely different approach, one guided by physical intuition. Françoise Ulam was one of a cadre of women “computers” who carried out laborious and extensive computations of thermonuclear scenarios on mechanical calculators, supplemented and confirmed by Everett’s slide rule. Ulam and Fermi collaborated on further analysis of these scenarios. The results showed that, in workable configurations, a thermonuclear reaction would not ignite, and if ignited, it would not be self-sustaining. Ulam had used his expertise in Combinatorics to analyze the chain reaction in deuterium, which was much more complicated than the ones in uranium and plutonium, and he concluded that no self-sustaining chain reaction would take place at the (low) densities that Teller was considering. In late 1950, these conclusions were confirmed by von Neumann’s results.
Für wen bildeten Spaghetti napoletana und bolognese, reichlich mit geriebenem Käse bestreut, nicht den Einstieg in die italienische Küche? Bestimmt haben auch Sie in den letzten Tagen ein Pastagericht genossen. Kein Wunder also, dass wir für diese besondere Spezialität die passenden Teller und Schüsseln entwickelt haben, perfekt für eine Portion Penne oder Spaghetti. Teller, die Sie sowohl beim gemütlichen Mittagessen mit der Familie als auch beim festlichen Diner verwenden können, um sie danach sorglos in den Geschirrspüler zu stellen. Teller, die Ihrem Tisch das gewisse Etwas verpassen, aber sich gleichzeitig nahtlos in Ihre Geschirrkollektion einfügen – das gelingt nur dem Design von Villeroy & Boch.
Für das Gericht, mit dem wir alle groß wurden Für wen bildeten Spaghetti napoletana und bolognese, reichlich mit geriebenem Käse bestreut, nicht den Einstieg in die italienische Küche? Bestimmt haben auch Sie in den letzten Tagen ein Pastagericht genossen. Kein Wunder also, dass wir für diese besondere Spezialität die passenden Teller und Schüsseln entwickelt haben, perfekt für eine Portion Penne oder Spaghetti. Teller, die Sie sowohl beim gemütlichen Mittagessen mit der Familie als auch beim festlichen Diner verwenden können, um sie danach sorglos in den Geschirrspüler zu stellen. Teller, die Ihrem Tisch das gewisse Etwas verpassen, aber sich gleichzeitig nahtlos in Ihre Geschirrkollektion einfügen – das gelingt nur dem Design von Villeroy & Boch.
The waiter returned, offering free desserts. “In that case, what’s the most expensive?” Teller asked. During the time they worked on the book, Penn and Teller wrote independently and sent material to each other by modem. “Then we praised the other person’s writing,” Teller said.
The clothing issue was settled in favor of the pair’s off-stage duds. Krasher was dismissed. A corner table was proffered. San Pellegrino water was ordered all around, and the menus came (“I like places with great portions,” Penn said. “Wow,” Teller said.) But as soon as the waiter taken the order (Teller said to the waiter, “Plain pasta”; Penn added garlic bread and salad), forks were suddenly seen hanging from the pair’s eyelids. Milk-colored glop spurted onto everyone’s clothes.
Soon, Pasta and Ulam became experienced with electronic computation on MANIAC, and by this time, Enrico Fermi had settled into a routine of spending academic years at the University of Chicago and summers at Los Alamos. During these summer visits, Pasta and Ulam joined him to study a variation of the classic problem of a string of masses held together by springs that exert forces linearly proportional to their displacement from equilibrium. Fermi proposed to add to this force a nonlinear component, which could be chosen to be proportional to either the square or cube of the displacement, or to a more complicated “broken linear” function. This addition is the key element of the Fermi–Pasta–Ulam problem, which is often designated by the abbreviation FPU.
Besonders viel mediterranes Herzblut steckt in der Kollektion Pasta Passion. Der Spaghettiteller ist perfekt für längliche Pasta, wie Tagliatelle oder Spaghetti. Die für die ganze Pastaserie so typische Aussparung am Tellerrand sorgt dafür, dass die Gabel nicht verrutscht oder vom Tellerrand fällt. Eine kleine Drehmulde hilft beim Aufdrehen, so dass jeder Pastaliebhaber auf einen Löffel verzichten kann. Kurze Nudeln wie Farfalle, Penne und Makkaroni können in der schlichten Pastaschüssel von Pasta Passion ebenfalls stilvoll serviert werden. Der Medium Pastateller, der dank seiner kleinen Schubskuhle am Rand auch perfekt für Tortellini geeignet ist, kann dabei als Deckel verwendet werden und das Gericht länger warm halten – das ist Innovation von Villeroy & Boch.