Universal deterministic quantum operations in microwave quantum links

TL;DR

This paper introduces a practical framework for implementing deterministic distributed quantum gates over microwave quantum links, enabling reliable quantum communication without the need for entanglement distribution or measurements.

Contribution

It develops a general formalism for universal quantum gates in microwave links, applicable to various modes and operational regimes, with detailed analysis of imperfections and high-fidelity protocols.

Findings

Design of fast, reliable state transfer protocols.

Implementation of deterministic universal quantum gates.

Identification of key imperfections and optimal operation points.

Abstract

We propose a realistic setup, inspired by already existing experiments, within which we develop a general formalism for the implementation of distributed quantum gates. Mediated by a quantum link that establishes a bidirectional quantum channel between distant nodes, our proposal works both for inter- and intra node communication and handles scenarios ranging from the few to the many modes limit of the quantum link. We are able to design fast and reliable state transfer protocols in every regime of operation, which, together with a detailed description of the scattering process, allows us to engineer two sets of deterministic universal distributed quantum gates. Gates whose implementation in quantum networks does not need entanglement distribution nor measurements. By employing a realistic description of the physical setup we identify the most relevant imperfections in the quantum links as well as optimal points of operation with resulting infidelities of $1-F \approx 10^{-2}-10^{-3}$.