Pinning quantum phase transition of photons in a hollow-core fiber

TL;DR

This paper proposes observing a pinning quantum phase transition of photons in a hollow-core fiber loaded with cold atoms, by creating a tunable lattice potential to explore strongly correlated photonic states.

Contribution

It introduces a method to realize and probe a pinning quantum phase transition of photons using a tunable lattice potential in a hollow-core fiber with cold atomic gas.

Findings

Identification of a phase diagram including Bose-Hubbard and sine-Gordon regimes

Proposal for measuring stationary excitations via propagating light pulses

Demonstration of creating strongly correlated photonic states

Abstract

We show that a pinning quantum phase transition for photons could be observed in a hollow-core one-dimensional fiber loaded with a cold atomic gas. Utilizing the strong light confinement in the fiber, a range of different strongly correlated polaritonic and photonic states, corresponding to both strong and weak interactions can be created and probed. The key ingredient is the creation of a tunable effective lattice potential acting on the interacting polaritonic gas which is possible by slightly modulating the atomic density. We analyze the relevant phase diagram corresponding to the realizable Bose-Hubbard (weak) and sine-Gordon (strong) interacting regimes and conclude by describing the measurement process. The latter consists of mapping the stationary excitations to propagating light pulses whose correlations can be efficiently probed once they exit the fiber using available optical technologies