Enhancing superconductivity using thermal bosons

TL;DR

This paper demonstrates that coupling a superconductor to thermal bosons can significantly increase its critical temperature, with a self-consistent renormalization group approach revealing the dependence on boson properties.

Contribution

It introduces a novel renormalization group framework to analyze how thermal bosons can enhance superconductivity, providing a phase diagram and potential experimental setups.

Findings

Critical temperature increases with boson coupling strength.

Critical temperature depends on boson mass and state.

Phase diagram shows regimes of enhanced superconductivity.

Abstract

We investigate how the strong coupling of a superconductor to thermal bosons can enhance its superconducting critical temperature. To tackle this problem, we use a renormalization group approach that allows us to describe the competition between density fluctuations and the build-up of boson-induced attraction between fermions. Capturing the mutual influence of bosonic and fermionic sectors, the self-consistent renormalization group framework predicts a robust increase of the critical temperature across a wide range of interactions. We find a nontrivial dependence of the critical temperature on the boson mass and we establish a phase diagram for enhanced superconductivity driven by bosons being either in the condensed or thermal state. We outline possible experimental realizations in cold atomic systems and discuss implementations using electron-exciton mixtures in van der Waals material heterostructures.