{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,17]],"date-time":"2025-10-17T13:59:02Z","timestamp":1760709542419,"version":"build-2065373602"},"reference-count":56,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2018,2,27]],"date-time":"2018-02-27T00:00:00Z","timestamp":1519689600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Entropy"],"abstract":"<jats:p>We analytically calculate the statistics of Bose-Einstein condensate (BEC) fluctuations in an interacting gas trapped in a three-dimensional cubic or rectangular box with the Dirichlet, fused or periodic boundary conditions within the mean-field Bogoliubov and Thomas-Fermi approximations. We study a mesoscopic system of a finite number of trapped particles and its thermodynamic limit. We find that the BEC fluctuations, first, are anomalously large and non-Gaussian and, second, depend on the trap\u2019s form and boundary conditions. Remarkably, these effects persist with increasing interparticle interaction and even in the thermodynamic limit\u2014only the mean BEC occupation, not BEC fluctuations, becomes independent on the trap\u2019s form and boundary conditions.<\/jats:p>","DOI":"10.3390\/e20030153","type":"journal-article","created":{"date-parts":[[2018,2,27]],"date-time":"2018-02-27T14:18:08Z","timestamp":1519741088000},"page":"153","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["Anomalous Statistics of Bose-Einstein Condensate in an Interacting Gas: An Effect of the Trap\u2019s Form and Boundary Conditions in the Thermodynamic Limit"],"prefix":"10.3390","volume":"20","author":[{"given":"Sergey","family":"Tarasov","sequence":"first","affiliation":[{"name":"Institute of Applied Physics, Russian Academy of Science, Nizhny Novgorod 603950, Russia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Vladimir","family":"Kocharovsky","sequence":"additional","affiliation":[{"name":"Institute of Applied Physics, Russian Academy of Science, Nizhny Novgorod 603950, Russia"},{"name":"Department of the Advanced School of General and Applied Physics, Lobachevsky State University, Nizhny Novgorod 603950, Russia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6802-3258","authenticated-orcid":false,"given":"Vitaly","family":"Kocharovsky","sequence":"additional","affiliation":[{"name":"Department of Physics and Astronomy, Texas A&amp;M University, College Station, TX 77843-4242, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2018,2,27]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Landau, L.D., and Lifshitz, E.M. 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