From coherent to fermionized microwave photons in a superconducting transmission line

TL;DR

This paper explores how superconducting transmission lines with Josephson junctions can host strongly interacting microwave photons, enabling the creation of fermionized photon states similar to a Tonks-Girardeau gas, with observable correlation signatures.

Contribution

It demonstrates the feasibility of achieving strongly interacting, fermionized microwave photons in superconducting transmission lines through adiabatic conversion techniques.

Findings

Strong photon-photon interactions are achievable with realistic parameters.

Adiabatic tapering can convert coherent fields into fermionized photon states.

Correlation properties reveal signatures of strong photon correlations.

Abstract

We investigate superconducting transmission lines as a novel platform for realizing a quantum fluid of microwave photons in a propagating geometry. We predict that the strong photon-photon interactions provided by the intrinsic nonlinearity of Josephson junctions are sufficient to enter a regime of strongly interacting photons for realistic parameters. A suitable tapering of the transmission line parameters allows for the adiabatic conversion of an incident coherent field into a Tonks-Girardeau gas of fermionized photons close to its ground state. Signatures of the strong correlations are anticipated in the correlation properties of the transmitted light.