Universality of vertex corrections to the electrical conductivity in models with elastically scattered electrons

TL;DR

This paper investigates how elastic scattering affects electrical conductivity in lattice fermions, showing that vertex corrections always reduce conductivity due to quantum coherence effects.

Contribution

It demonstrates that vertex corrections to conductivity are negative in elastic scattering models, highlighting a universal quantum coherence effect.

Findings

Vertex corrections are negative for elastic scatterings.

Quantum coherence reduces diffusion in these models.

The effect is consistent for both thermal and static impurities.

Abstract

We study quantum coherence of elastically scattered lattice fermions. We calculate vertex corrections to the electrical conductivity of electrons scattered either on thermally equilibrated or statically distributed random impurities. We demonstrate that the sign of the vertex corrections to the Drude conductivity is in both cases negative. Quantum coherence due to elastic back-scatterings always leads to diminution of diffusion.