Superconductivity in the Two-Band Hubbard Model in Infinite Dimensions

TL;DR

This paper investigates superconductivity in a two-band Hubbard model in infinite dimensions, revealing metal-insulator transitions and a superconducting state with a frequency-dependent order parameter through analytical and Monte Carlo methods.

Contribution

It introduces a novel analysis of superconductivity in the two-band Hubbard model using extended algorithms and numerical evidence in the infinite-dimensional limit.

Findings

Normal state exhibits metal-insulator transitions.

Superconducting state with frequency-dependent order parameter identified.

Numerical evidence shows instability of the normal state against superconductivity.

Abstract

We study a two-band Hubbard model in the limit of infinite dimensions, using a combination of analytical methods and Monte-Carlo techniques. The normal state is found to display various metal to insulators transitions as a function of doping and interaction strength. We derive self-consistent equations for the local Green's functions in the presence of superconducting long-range order, and extend previous algorithms to this case. We present direct numerical evidence that in a specific range of parameter space, the normal state is unstable against a superconducting state characterized by a strongly frequency dependent order-parameter.