# Transport of neutral optical excitations using electric fields

## TL;DR

This paper reveals a nonperturbative Coulomb drag effect where electric fields induce a drag force on neutral excitations like excitons and polaritons in a fermionic bath, enabling electrical and optical control of these quasiparticles.

## Contribution

It introduces a theoretical framework for Coulomb drag on neutral excitations, applying it to excitons and polaritons in doped semiconductors, and suggests new control methods for quantum impurities.

## Key findings

- Demonstrates a significant drag force on neutral excitations due to electric fields.
- Calculates frequency-dependent transconductivity in a self-consistent manner.
- Proposes electrical and optical manipulation of excitons and polaritons.

## Abstract

Mobile quantum impurities interacting with a fermionic bath form quasiparticles known as Fermi polarons. We demonstrate that a force applied to the bath particles can generate a drag force of similar magnitude acting on the impurities, realizing a novel, nonperturbative Coulomb drag effect. To prove this, we calculate the fully self-consistent, frequency-dependent transconductivity at zero temperature in the Baym-Kadanoff conserving approximation. We apply our theory to excitons and exciton polaritons interacting with a bath of charge carriers in a doped semiconductor embedded in a microcavity. In external electric and magnetic fields, the drag effect enables electrical control of excitons and may pave the way for the implementation of gauge fields for excitons and polaritons. Moreover, a reciprocal effect may facilitate optical manipulation of electron transport. Our findings establish transport measurements as a novel, powerful tool for probing the many-body physics of mobile quantum impurities.