Analyticity of the one-particle density matrix

TL;DR

This paper proves that the one-particle density matrix in multi-particle quantum systems is analytic everywhere except at the nuclei and along the diagonal where x equals y.

Contribution

It establishes the analyticity of the one-particle density matrix away from singularities, providing new mathematical insights into quantum many-body systems.

Findings

Density matrix is analytic away from nuclei.

Density matrix is analytic away from the diagonal x=y.

Provides rigorous proof of analyticity properties.

Abstract

It is proved that the one-particle density matrix $\gamma(x, y)$ for multi-particle systems is analytic away from the nuclei and from the diagonal $x = y$.