Spin-wave quantum computing with atoms in a single-mode cavity

Abstract

We present a method for network-capable quantum computing that relies on holographic spin-wave excitations stored collectively in ensembles of qubits. We construct an orthogonal basis of spin waves in a one-dimensional array and show that high-fidelity universal linear controllability can be achieved using only phase shifts, applied in both momentum and position space. Neither single-site addressability nor high single-qubit cooperativity is required, and the spin waves can be read out with high efficiency into a single cavity mode for quantum computing and networking applications. We describe how to establish linear quantum processing using a lambda scheme in a rubidium-atom system and calculate the expected experimental operational fidelities due to fundamental and technical errors. We derive efficient methods to achieve linear controllability in both a single-ensemble and dual-ensemble configuration. 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.