Lev Landau and the conception of neutron stars

TL;DR

This paper explores the early history and theoretical predictions of neutron stars, highlighting Landau's pioneering ideas before the neutron's discovery and clarifying historical misconceptions.

Contribution

It presents new historical evidence that Landau's 1931 paper predicted neutron stars prior to the neutron's discovery, correcting previous assumptions.

Findings

Landau's 1931 paper anticipated neutron star concepts.

The discussion with Bohr and Rosenfeld likely occurred in March 1931.

Landau contributed to white dwarf and neutron star theories.

Abstract

We review the history of neutron star physics in the 1930s that is related to L. Landau. According to recollections of Rosenfeld (1974, Proc. 16th Solvay Conference on Physics, p. 174), Landau improvised the concept of neutron stars in a discussion with Bohr and Rosenfeld just after the news of the discovery of the neutron reached Copenhagen in February 1932. We present arguments that the discussion took place in March 1931, before the discovery of the neutron, and that they in fact discussed the paper written by Landau in Zurich in February 1931 but not published until February 1932 (Phys. Z. Sowjetunion, 1, 285). In his paper Landau mentioned the possible existence of dense stars which look like one giant nucleus; this can be regarded as an early theoretical prediction or anticipation of neutron stars, prior to the discovery of the neutron. The coincidence of the dates of the neutron's discovery and the paper's publication has led to an erroneous association of the paper with the discovery of the neutron. In passing, we outline the contribution of Landau to the theory of white dwarfs and to the hypothesis of stars with neutron cores.