2014/12/01 by V. V. Kocharovsky, Vitaly V. Kocharovsky, Vladimir V. Kocharovsky
Mathematics · Physics and Astronomy · #Bose gas #Bose–Einstein condensate #Cold Atom Physics and Bose-Einstein Condensates #Condensation #Condensed matter physics #Critical phenomena #Limit (mathematics) #Mathematics #Microscopic theory #Phase (matter) #Phase transition #Physics #Quantum critical point #Quantum mechanics #Quantum phase transition #Quantum, superfluid, helium dynamics #Strong Light-Matter Interactions #Thermodynamics #cond-mat.quant-gas #cond-mat.stat-mech
paper · pdf · doi:10.1016/j.physleta.2014.10.052
published as Physics Letters A 379, 466-470 (2015) · 5 pages
openalex publication_date 2014/12/01 · arxiv created 2015/10/26 · arxiv updated 2015/11/27 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
We present a microscopic theory of the second order phase transition in an interacting Bose gas that allows one to describe formation of an ordered condensate phase from a disordered phase across an entire critical region continuously. We derive the exact fundamental equations for a condensate wave function and the Green functions, which are valid both inside and outside the critical region. They are reduced to the usual Gross-Pitaevskii and Beliaev-Popov equations in a low-temperature limit outside the critical region. The theory is readily extendable to other phase transitions, in particular, in the physics of condensed matter and quantum fields.