Photon BEC with Thermo-Optic Interaction at Dimensional Crossover

Abstract

Since the advent of experiments with photon Bose-Einstein condensates in dye-filled microcavities in 2010, many investigations have focused upon the emerging effective photon-photon interaction. Despite its smallness, it can be identified to stem from two physically distinct mechanisms. On the one hand, a Kerr nonlinearity of the dye medium yields a photon-photon contact interaction. On the other hand, a heating of the dye medium leads to an additional thermo-optic interaction, which is both delayed and non-local. The latter turns out to represent the leading contribution to the effective interaction for the current 2D experiments. Here we analyse theoretically how the effective photon-photon interaction increases when the system dimension is reduced from 2D to 1D. To this end, we consider an anisotropic harmonic trapping potential and determine via a variational approach how the properties of the photon Bose-Einstein condensate in general, and both aforementioned interaction mechanisms in particular, change with increasing anisotropy. We find that the thermo-optic interaction strength increases at first linearly with the trap aspect ratio and lateron saturates at a certain value of the trap aspect ratio. Furthermore, in the strong 1D limit the roles of both interactions get reversed as the thermo-optic interaction remains saturated and the contact Kerr interaction becomes the leading interaction mechanism. Finally, we discuss how the predicted effects can be measured experimentally.

16 pages, 4 figures

References in corpus (7)

• Many-Body Physics with Ultracold Gases
• Bose-Einstein condensation of photons in an optical microcavity
• Thermalisation of a two-dimensional photonic gas in a 'white-wall' photon box
• Interacting Bose gases in quasi-one dimensional optical lattices
• Connecting Berezinskii-Kosterlitz-Thouless and BEC phase transitions by tuning interactions in a trapped gas
• Cross-dimensional phase transition from an array of 1D Luttinger liquids to a 3D Bose-Einstein condensate
• Dimensional crossover of Bose-Einstein condensation phenomena in quantum gases confined within slab geometries

Cited by in corpus (5)

• Dimensional Crossover in a Quantum Gas of Light
• Hartree-Fock Analogue Theory of Thermo-Optic Interaction
• Exact Diagonalisation of Photon Bose-Einstein Condensates with Thermo-Optic Interaction
• Nonlocality-induced surface localization in Bose-Einstein condensates of light
• Projection Optimization Method for Open-Dissipative Quantum Fluids and its Application to a Single Vortex in a Photon Bose-Einstein Condensate