Berlin: Julius Springer, 1932. 1st Edition. FIRST EDITION OF THE FIRST OF HEISENBERG’S 3 PAPERS PRESENTING THE FINAL MATHEMATICAL MODEL OF THE ATOM. Heisenberg’s seminal work, beginning here with ‘On the Structure of the Atomic Nuclei I,’ “mark[ed] the transition to the modern view on nuclear forces” (Pais, Inward Bound, 413).
In 1932, Heisenberg received the Nobel Prize for “the creation of quantum mechanics.” Until that same year, he “was convinced that quantum mechanics was insufficient to describe the atomic nucleus just as classical physics had been insufficient to describe the atom” (Brandt, The Harvest of the Century, pp. 223-224). But in early 1932, Chadwick announced his discovery of the neutron, making clear that rather than being composed of a proton and an electron, a neutron was a particle in its own right. The discovery "made it possible to change the relation between nuclear physics and the domain of unsolved problems. A substantial number of nuclear problems now became solvable by ordinary quantum mechanics" (ibid). Still, "once it was accepted that the nucleus was composed of protons and neutrons and that quantum mechanics could be applied to it, the question remained which force acted between its constituents. Heisenberg assumed it to be an exchange force, i.e., a force based on the symmetry properties of a quantum-mechanical wave function" (ibid).
In June of 1932, only a few months after Chadwick's discovery, Heisenberg used Chadwick’s neutron to construct the first quantum mechanical nuclear model and published his work in the paper offered here. “In the introductory paragraph he points out that the structure of nuclei can be explained in the framework of quantum mechanics if proton and neutron are taken as elementary but that fundamental difficulties remain if the decay of a neutron into a proton and an electron is considered. He thus clearly separated the question of nuclear structure from that of Beta decay. In a letter to Bohr, he explained: ‘The basic idea is to shift all difficulties of principle to the neutron and to deal with the nucleus by [ordinary] quantum mechanics.’
In this [first] paper and its two sequels, he tried to answer both questions” (Brandt). The main mechanism he proposed was an exchange force produced by protons and neutrons passing electrons around like basketball players tossing a ball" (Peacock, The Quantum Revolution, 94). Heisenberg postulated that the proton and neutron were two states of the same particle, the nucleon, differing only in isospin. In his theory, the nuclear force conserved isospin, which accounted for the similarities between protons and neutrons. Other forces, such as electromagnetism, broke isospin symmetry, which explained the nucleons' differences. Heisenberg was wrong about the nature of the proton and neutron, but was correct about the importance of isospin in the weak nuclear force. Heisenberg's theory was "quantitatively insufficient to explain nuclear forces... [and] the riddle of nuclear forces stayed a subject of research for decades to come.
“The lasting value of Heisenberg's approach lies in the revelation of inner symmetries of elementary particles and of quantum numbers associated with these symmetries. The discovery of further symmetries of this type would lead first to a classification of particles and then to an understanding of the forces between them" (Brandt, 226).
ALSO: Bethe & Fermi, “Über die Wechselwirkung von zwei Elektronen,” pp. 296-306. Item #1415
CONDITION: Berlin: Julius Springer. Volume 77. 837 pp. NOT ex-library. Solidly and cleanly bound in blue cloth, gilt-lettered at the spine. As is typical of German volumes of this era, minor age toning within; some old creasing. Very good condition. “Über den Bau der Atomkerne I,” pp. 1-11.