Heisenberg asks Pauli if he would be ready to take over part of the paper to be given at the Solvay congress on elementary particles: 1) "on the general properties of elementary particles", 2) "the special empirical forms of interaction and their consequences", 3) "the limitations of the present theory". He was interested in what Fierz told him about gravitational quanta of spin 2.
Heisenberg, WernerHeisenberg replies to Pauli's letter. He does not fully agree with Pauli that the inertia of self-energy of the spin is of the order (M.c)/h, because the absorptions of mesons indicate a much smaller cross-section for scattering by protons such as that of Bhabha-Heitler, and because the additional inertia does not change the nuclear forces. The spin-inertia plays a role only in the case of rapidly changing fields. He agrees with Pauli's remark on electron spin.
Heisenberg, WernerHeisenberg has sent copy of his Solvay-report also to Bohr. He writes about his trip to the USA.
Heisenberg, WernerHeisenberg asks about the program of the forthcoming conference in Zürich.
Heisenberg, WernerHeisenberg explains his ideas about the "Vertauschungsrelationen" (interchange relations) in his paper. The real problem arises after the introduction of an interaction. This belongs to the general question: which invariance conditions are fullfilled by the interaction energy? He is not as pessimistic as Pauli, the whole question boils down to the problem of finding suitable expressions for interaction out of combinations of wavefunctions which obey regular interchange relations. One has to begin by forming models for unitary theories which afterwards will split up in theories for single particles. The postulate of "hermiticity" is connected with the conservation law for nucleons.
Heisenberg, WernerHeisenberg thanks Pauli for the invitation to the symposium in Zurich.
Heisenberg, WernerHeisenberg must cancel his participation in the philosophical congress in Zurich because of his journey to the U.S.A.
Heisenberg, WernerHeisenberg comments on Pauli's calculations on the Lee model. He writes about his own work, especially on Bosons of zero mass in his model.
Heisenberg, WernerHeisenberg writes on the application of Pauli's ideas to quantum electrodynamics and on the avoidance of ghosts.
Heisenberg, WernerHeisenberg talks about some relations between Lee's theory and his.
Heisenberg, Werner