Basic Variables to Be Reproduced in the First-Principles Theory for Superconductors: Fluctuation of the Particle Number

2015/12/24 by Katsuhiko Higuchi, Masahiko Higuchi, Eina Miki
Chemistry · Materials Science · Physics and Astronomy · #Advanced Physical and Chemical Molecular Interactions #Diagonal #Iron-based superconductors research #Particle (ecology) #Particle density #Particle number #Physics of Superconductivity and Magnetism #Probability density function #Variable (mathematics) #Variables #cond-mat.supr-con

paper · pdf · doi:10.7566/jpsj.86.064704

published as J. Phys. Soc. Jpn. 86, 064704/1-11 (2017) · no figure

arxiv created 2015/12/24 · openalex created_date 2016/06/24 · openalex publication_date 2017/05/11 · arxiv updated 2017/05/26 · openalex updated_date 2026/08/05

Abstract

We show that the diagonal elements of the second-order reduced density matrix (RDM2) can be chosen as basic variables for describing the superconducting state, instead of the off-diagonal elements of the RDM2 that are usually adopted as basic variables in the density functional scheme. The diagonal elements of the RDM2 are called pair-density (PD), which is explicitly related to the fluctuation of the particle number of the system. In this paper, we argue that the fluctuation of the particle number can become an indication of the superconducting state, and that the density functional scheme in which the PD is chosen as a basic variable would be a promising first-principles theory for superconductors.

Citations

• On a new method in the theory of superconductivity
• Theory of Superconductivity
• Bound Electron Pairs in a Degenerate Fermi Gas
• Density functional theory for superconductors with particle-hole asymmetric electronic structure
• Arbitrary choice of basic variables in density functional theory: Formalism
• N-representability of two-electron densities and density matrices and the application to the few-body problem