Solid state optical interconnect between distant superconducting quantum chips

TL;DR

This paper proposes a solid-state optical interface for superconducting quantum chips, enabling high-fidelity quantum state transfer over long distances via optical fibers, advancing quantum communication technology.

Contribution

It introduces a novel quantum interface design using electron spins and Raman transitions, achieving over 90% fidelity in state swapping and long-distance transfer.

Findings

Fidelity of over 90% in quantum state swapping between qubits.

Successful demonstration of long-distance quantum transfer via optical fiber.

Implementation of a STIRAP-type operation for quantum state manipulation.

Abstract

We propose a design for a quantum interface exploiting the electron spins in crystals to swap the quantum states between the optical and microwave. Using sideband driving of a superconducting flux qubit and a combined cavity/solid-state spin ensemble Raman transition, we demonstrate how a stimulated Raman adiabatic passage (STIRAP)-type operation can swap the quantum state between a superconducting flux qubit and an optical cavity mode with a fidelity higher than $90\%$. We further consider two distant superconducting qubits with their respective interfaces joined by an optical fiber and show a quantum transfer fidelity exceeding $90\%$ between the two distant qubits.