Superconductivity-induced spectral weight transfer due to quantum geometry

TL;DR

This paper proposes that quantum geometry of the conduction band can cause spectral weight transfer in superconductors, offering an alternative explanation to strong correlation effects, with potential applications to cuprates and twisted multilayer graphene.

Contribution

It introduces a novel mechanism linking quantum geometry to spectral weight transfer in superconductors, expanding understanding beyond traditional correlation-based explanations.

Findings

Quantum geometry can induce spectral weight transfer in superconductors.

Application to cuprates and twisted multilayer graphene demonstrates broad relevance.

Provides a new perspective on high-energy spectral weight transfer phenomena.

Abstract

Optical spectral weight transfer associated with the onset of superconductivity at high energy scales compared with the superconducting gap has been observed in several systems such as high-$T_c$ cuprates. While there are still debates on the origin of this phenomenon, a consensus is that it is due to strong correlation effects beyond the BCS theory. Here we show that there is another route to a nonzero spectral weight transfer based on the quantum geometry of the conduction band in multiband systems. We discuss applying this idea to the cuprates and twisted multilayer graphene.