Effects of finite trapping on the decay, recoil, and decoherence of dark states of quantum emitter arrays

TL;DR

This paper investigates how finite trap strength and light-mediated forces influence the decay, recoil, and decoherence of dark states in atomic arrays, with implications for quantum memories and information storage.

Contribution

It introduces a detailed analysis of vibrational effects on subradiant states in atomic arrays, considering finite trapping and forces, which was not thoroughly explored before.

Findings

Recoil energy can reach a vibrational quantum even in the Lamb-Dicke regime.

Vibrational wavepackets are shifted or distorted in weak traps due to forces.

Entanglement entropy and infidelity can be reduced by stronger traps or weaker forces.

Abstract

The collective interaction of electronic excitations with the electromagnetic field in atomic arrays can lead to reduced decay rates, forming subradiant states with applications in quantum information and memories. By including quantized vibrational excitations, we examine the effects of finite trap strength and light-mediated forces on highly subradiant singly-excited states for two, three, and many atoms in a 1D waveguide or free space. For waveguide-coupled and tightly trapped atoms, the recoil energy from photon emission can reach a vibrational quantum, even in the Lamb-Dicke regime. For weakly trapped atoms, the vibrational wavepackets are shifted or distorted due to induced forces and uneven decay. These effects lead to a time-dependent decay rate, extra vibrational energy transfer, and mixing of different electronic and vibrational states. The resulting entanglement entropy and infidelity can be mitigated by decreasing the induced forces or increasing trap strength. For quantum information storage, these findings suggest optimal array configurations in geometry and polarization. Our results provide insights for quantum memories and atom array experiments.