Superconductivity and the BCS-Bogoliubov Theory

Abstract

First, we reformulate the BCS-Bogoliubov theory of superconductivity from the viewpoint of linear algebra. We define the BCS Hamiltonian on ${\mathbb{C}}^{2^{2M}}$, where $M$ is a positive integer. We discuss selfadjointness and symmetry of the BCS Hamiltonian as well as spontaneous symmetry breaking. Beginning with the gap equation, we give the well-known expression for the BCS state and find the existence of an energy gap. We also show that the BCS state has a lower energy than the normal state. Second, we introduce a new superconducting state explicitly and show from the viewpoint of linear algebra that this new state has a lower energy than the BCS state. Third, beginning with our new gap equation, we show from the viewpoint of linear algebra that we arrive at the results similar to those in the BCS-Bogoliubov theory.

15 pages

Cited by in corpus (4)

• Variational Principle of Bogoliubov and Generalized Mean Fields in Many-Particle Interacting Systems
• The solution to the BCS gap equation and the second-order phase transition in superconductivity
• Is the solution to the BCS gap equation continuous in the temperature ?
• Smoothness of the Gap Function in the BCS-Bogoliubov Theory of Superconductivity