Hybrid light-matter excitations and spontaneous time-reversal symmetry breaking in two-dimensional Josephson Junctions

TL;DR

This paper explores how hybrid light-matter interactions in graphene-based Josephson junctions can lead to spontaneous time-reversal symmetry breaking and hybridized excitations, with potential implications for quantum technologies.

Contribution

It introduces a mean-field analysis of light-matter coupling effects in 2D superconductor-semiconductor systems, revealing symmetry breaking and hybrid excitations.

Findings

Current-phase relation shows signs of spontaneous time-reversal symmetry breaking.

Identifies low-energy spectrum of hybridized light-matter excitations.

Demonstrates tunability via Fermi level and temperature.

Abstract

In the context of hybrid superconductor-semiconductor systems, Josephson junctions based on two-dimensional materials, such as graphene, offer promising opportunities because of their scalability and gate-tunable electronic properties. In this work, we investigate the inductive coupling between a quantum LC resonator and a superconducting loop embedding a short, ballistic, planar Josephson junction, with the graphene-based case as a representative example. Within a mean-field formalism, we analyze how the properties of the global system depend on the light-matter interaction coupling, the Fermi level of the two-dimensional material, and temperature. Our findings reveal that the current-phase relation can show features indicative of spontaneous time-reversal symmetry breaking. Furthermore, starting from the mean-field theory, we determine the low-energy spectrum of collective hybridized light-matter excitations.