Thermally Condensing Photons into a Coherently Split State of Light

TL;DR

This paper demonstrates that photons can be thermally condensed into a coherent split state within a microcavity, enabling room-temperature quantum control of light with potential for new quantum states.

Contribution

It introduces a thermodynamic method to split and control photon states in an optical microcavity, a novel approach in quantum optics.

Findings

Photons condense into a coherent bifurcated ground state at room temperature.

Interference fringes confirm coherence between split photon states.

The method functions as a thermodynamic beamsplitter for photons.

Abstract

Techniques to control the quantum state of light play a crucial role in a wide range of fields, from quantum information science to precision measurements. While for electrons in solid state materials complex quantum states can be created by mere cooling, in the field of optics manipulation and control currently builds on non-thermodynamic methods. Using an optical dye microcavity, we have split photon wavepackets by thermalization within a potential with two minima subject to tunnel coupling. Even at room temperature, photons condense into a quantum-coherent bifurcated ground state. Fringe signals upon recombination show the relative coherence between the two wells, demonstrating a working interferometer with the non-unitary thermodynamic beamsplitter. This energetically driven optical state preparation opens up an avenue for exploring novel correlated and entangled optical manybody states.