# Subradiance-protected excitation transport

## TL;DR

This paper demonstrates that in a one-dimensional atomic chain, excitation transport can be made highly subradiant, enabling long-lived, dispersionless wave packet transport controllable by magnetic fields, with potential applications in energy transfer and light storage.

## Contribution

It reveals the existence of subradiant states with linear dispersion in a 1D atomic chain, enabling long-distance, low-loss excitation transport with controllable direction and velocity.

## Key findings

- Transport is subradiant with significantly extended lifetimes.
- Subradiant states exhibit linear dispersion enabling dispersionless transport.
- Transport properties can be controlled via external magnetic fields.

## Abstract

We explore excitation transport within a one-dimensional chain of atoms where the atomic transition dipoles are coupled to the free radiation field. When the atoms are separated by distances smaller or comparable to the wavelength of the transition, the exchange of virtual photons leads to the transport of the excitation through the lattice. Even though this is a strongly dissipative system, we find that the transport is subradiant, that is, the excitation lifetime is orders of magnitude longer than the one of an individual atom. In particular, we show that a subspace of the spectrum is formed by subradiant states with a linear dispersion relation, which allows for the dispersionless transport of wave packets over long distances with virtually zero decay rate. Moreover, the group velocity and direction of the transport can be controlled via an external uniform magnetic field while preserving its subradiant character. The simplicity and versatility of this system, together with the robustness of subradiance against disorder, makes it relevant for a range of applications such as lossless energy transport and long-time light storage.