Quantum memory for microwave photons in an inhomogeneously broadened spin ensemble

TL;DR

This paper introduces a multi-mode quantum memory protocol that uses spin-echo techniques to significantly extend the storage time of microwave photon states in an ensemble of electronic spins, achieving high fidelity.

Contribution

It presents a novel quantum memory scheme that protects against inhomogeneous broadening, enabling longer storage times for microwave photons in spin ensembles.

Findings

Memory times are orders of magnitude longer than previous methods.

Achieves 80% fidelity in storing qubits encoded in Fock states.

Uses NV center spins in diamond for practical implementation.

Abstract

We propose a multi-mode quantum memory protocol able to store the quantum state of the field in a microwave resonator into an ensemble of electronic spins. The stored information is protected against inhomogeneous broadening of the spin ensemble by spin-echo techniques resulting in memory times orders of magnitude longer than previously achieved. By calculating the evolution of the first and second moments of the spin-cavity system variables for realistic experimental parameters, we show that a memory based on NV center spins in diamond can store a qubit encoded on the |0> and |1> Fock states of the field with 80% fidelity.