Quantum processing with ensembles of rare earth ions in a stoichiometric crystal

TL;DR

This paper proposes a method for creating small quantum processors using ensembles of rare earth ions in a crystal, enabling quantum memory, operations, and error correction within a solid-state platform.

Contribution

It introduces a novel approach to quantum processing by leveraging ensembles of rare earth ions in a stoichiometric crystal for qubit implementation and quantum operations.

Findings

Ensembles of ions serve as qubits with unique optical and hyperfine frequencies.

Strong local interactions enable quantum operations and linear transformations.

The system supports quantum memory and error correction protocols.

Abstract

We describe a method for creating small quantum processors in a crystal stoichiometric in an optically active rare earth ion. The crystal is doped with another rare earth, creating an ensemble of identical clusters of surrounding ions, whose optical and hyperfine frequencies are uniquely determined by their spatial position in the cluster. Ensembles of ions in each unique position around the dopant serve as qubits, with strong local interactions between ions in different qubits. These ensemble qubits can each be used as a quantum memory for light, and we show how the interactions between qubits can be used to perform linear operations on the stored photonic state. We also describe how these ensemble qubits can be used to enact, and study, error correction.