# Zero bias anomaly out of equilibrium

## TL;DR

This paper investigates the non-equilibrium zero bias anomaly in diffusive metals, deriving an effective action and showing how inelastic scattering smooths out the singularities seen in equilibrium.

## Contribution

It introduces a new effective action framework for out-of-equilibrium fluctuations and explains the smoothing of the ZBA due to inelastic processes.

## Key findings

- Inelastic scattering removes the singular behavior of the equilibrium ZBA.
- Derived an effective action describing virtual fluctuations out-of-equilibrium.
- Provided insights into the non-equilibrium tunneling density of states.

## Abstract

The non-equilibrium zero bias anomaly (ZBA) in the tunneling density of states of a diffusive metallic film is studied. An effective action describing virtual fluctuations out-of-equilibrium is derived. The singular behavior of the equilibrium ZBA is smoothed out by real processes of inelastic scattering.