Chiral SQUID-metamaterial waveguide for circuit-QED

TL;DR

This paper proposes a chiral waveguide using a spatiotemporally modulated superconducting metamaterial, enabling unidirectional photon transport and advanced quantum network functionalities in circuit-QED systems.

Contribution

It introduces a novel method to engineer a 1D Josephson metamaterial as a chiral waveguide with programmable modulation, enabling unidirectional photon propagation in circuit-QED.

Findings

Unidirectional photon propagation due to Brillouin scattering.

Superconducting qubits can dissipate photons unidirectionally.

Extension to cascaded quantum networks with remote qubits.

Abstract

Superconducting metamaterials, which are designed and fabricated with structured fundamental circuit elements, have motivated recent developments of exploring unconventional quantum phenomena in circuit quantum electrodynamics (circuit-QED). We propose a method to engineer 1D Josephson metamaterial as a chiral waveguide by considering a programmed spatiotemporal modulation on its effective impedance. The modulation currents are in the form of traveling waves which phase velocities are much slower than the propagation speed of microwave photons. Due to the Brillouin-scattering process, non-trivial spectrum regimes where photons can propagate unidirectionally emerge. Considering superconducting qubits coupling with this metamaterial waveguide, we analyze both Markovian and non-Markovian quantum dynamics, and find that superconducting qubits can dissipate photons unidirectionally. Moreover, we show that our proposal can be extended a cascaded quantum network with multiple nodes, where chiral photon transport between remote qubits can be realized. Our work might open the possibilities to exploit SQUID metamaterials for realizing unidirectional photon transport in circuit-QED platforms.