Mapping multiple photonic qubits into and out of one solid-state atomic ensemble

TL;DR

This paper demonstrates the coherent and reversible storage of 64 optical time-bin qubits in a solid-state atomic ensemble using a high-bandwidth atomic frequency comb, advancing scalable quantum memory technology.

Contribution

It introduces a method for storing multiple photonic qubits in a single solid-state ensemble with high efficiency and coherence, enabling scalable quantum networks.

Findings

Stored 64 optical modes at the single photon level.

Achieved a 1 microsecond storage time with high coherence.

Successfully stored and analyzed multiple time-bin qubits simultaneously.

Abstract

The future challenge of quantum communication are scalable quantum networks, which require coherent and reversible mapping of photonic qubits onto stationary atomic systems (quantum memories). A crucial requirement for realistic networks is the ability to efficiently store multiple qubits in one quantum memory. Here we demonstrate coherent and reversible mapping of 64 optical modes at the single photon level in the time domain onto one solid-state ensemble of rare-earth ions. Our light-matter interface is based on a high-bandwidth (100 MHz) atomic frequency comb, with a pre-determined storage time of 1 microseconds. We can then encode many qubits in short <10 ns temporal modes (time-bin qubits). We show the good coherence of the mapping by simultaneously storing and analyzing multiple time-bin qubits.