# Manifestation of Fermi edge singularity in the cotunneling regime

## TL;DR

This paper investigates how the Fermi edge singularity influences cotunneling in quantum dots, revealing universal power laws governed by electron scattering phases due to Coulomb interactions.

## Contribution

It introduces a bosonic model to analyze FES effects on cotunneling, providing multiscale current dependence and identifying universal power laws from electron scattering phases.

## Key findings

- Current exhibits multiscale dependence on QD level energy and bias.
- Universal power laws are determined by scattering phases.
- FES significantly modifies cotunneling behavior.

## Abstract

The Fermi edge singularity (FES) is a prominent manifestation of the Coulomb interaction. It can be observed in a controllable way by studying the transport through a quantum dot (QD), which is electrostatically coupled to the leads. In this paper we study how FES affects higher order tunneling processes (cotunneling). To address this problem we use the bosonic description of the electrons in the leads, which naturally accounts for the Coulomb interaction. We report the multiscale dependence of the current through the QD on the energy of the QD level and on the bias between the leads obtained for the limit of large and small bias. The new universal powers are determined by the scattering phases due to the interaction of electrons in the leads with the charge on the QD.