Linear and continuous variable spin-wave processing using a cavity-coupled atomic ensemble

TL;DR

This paper proposes a theoretical framework for using atomic spin waves in a cavity-coupled ensemble to perform universal quantum processing, including linear and continuous-variable operations, with high fidelity and scalability.

Contribution

It introduces a novel method for linear controllability with a single atomic ensemble and details schemes for universal quantum processing using spin waves in a cavity.

Findings

Calculated experimental operational fidelities for linear quantum processing.

Derived an efficient method for linear controllability with a single ensemble.

Proposed schemes for generating large dual-rail cluster states for deterministic quantum computing.

Abstract

Spin-wave excitations in ensembles of atoms are gaining attention as a quantum information resource. However, current techniques with atomic spin waves do not achieve universal quantum information processing. We conduct a theoretical analysis of methods to create a high-capacity universal quantum processor and network node using an ensemble of laser-cooled atoms, trapped in a one-dimensional periodic potential and coupled to a ring cavity. We describe how to establish linear quantum processing using a lambda-scheme in a rubidium-atom system, calculate the expected experimental operational fidelities. Second, we derive an efficient method to achieve linear controllability with a single ensemble of atoms, rather than two-ensembles as proposed in [K. C. Cox et al. Spin-Wave Quantum Computing with Atoms in a Single-Mode Cavity, preprint 2021]. Finally, we propose to use the spin-wave processor for continuous-variable quantum information processing and present a scheme to generate large dual-rail cluster states useful for deterministic computing.