THE THERMODYNAMIC CONTACT ANGLE IN THE PREWETTING PHASE OF A BINARY BOSE-EINSTEIN CONDENSATE MIXTURE

DOI: 10.18173/2354-1059.2025-0035

Abstract

To investigate the prewetting state of a Bose-Einstein condensate (BEC) mixture adsorbed on an optical hard wall at zero temperature, we consider a system in which condensate 1 coexists with condensate 2 with the chemical potential held fixed. Using the double parabola approximation (DPA) and solving the coupled Gross-Pitaevskii equations, we derive an analytical expression for the thermodynamic contact angle based on Youngs equation. Although the resulting formula is not algebraically simple, it reveals that complete wetting can occur before the bulk coexistence point is reached, indicating the presence of a continuous (second-order) prewetting transition. Our findings are in agreement with theoretical predictions in the literature and emphasize that the wetting film thickness grows smoothly without a discontinuous jump. This work provides useful guidance for the design of experiments aimed at observing wetting phenomena in Bose-Einstein condensates.