Speaker
Description
We investigate a two-component Bose mixture with repulsive intra- and interspecies interactions in two and three spatial dimensions. In three dimensions, we analyse the global structure of the phase diagram, the order of the phase transitions, and the associated universality classes using mean-field theory and the functional renormalisation group. The system exhibits four distinct phases: a normal phase, two single-component condensed phases, and a phase characterised by the simultaneous condensation of both components. Mean-field theory captures the principal phase structure, while the functional renormalisation group incorporates long-wavelength fluctuation effects, primarily leading to quantitative shifts of the phase boundaries. In two dimensions, we focus on the role of thermal fluctuations, which preclude true long-range order at finite temperature and place the system in the regime of Berezinskii–Kosterlitz–Thouless physics. Our results show how dimensionality and fluctuation effects shape the stability of condensate phases in multicomponent Bose systems.
| Affiliation | Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland |
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| Career status | PhD student |