[{"article_processing_charge":"No","arxiv":1,"year":"2020","author":[{"id":"30C4630A-F248-11E8-B48F-1D18A9856A87","last_name":"Mayer","first_name":"Simon","full_name":"Mayer, Simon"},{"last_name":"Seiringer","orcid":"0000-0002-6781-0521","id":"4AFD0470-F248-11E8-B48F-1D18A9856A87","first_name":"Robert","full_name":"Seiringer, Robert"}],"date_updated":"2025-07-10T11:55:05Z","main_file_link":[{"url":"https://arxiv.org/abs/2002.08281","open_access":"1"}],"isi":1,"department":[{"_id":"RoSe"}],"volume":61,"scopus_import":"1","type":"journal_article","publisher":"AIP Publishing","intvolume":"        61","abstract":[{"lang":"eng","text":"We prove an upper bound on the free energy of a two-dimensional homogeneous Bose gas in the thermodynamic limit. We show that for a2ρ ≪ 1 and βρ ≳ 1, the free energy per unit volume differs from the one of the non-interacting system by at most 4πρ2|lna2ρ|−1(2−[1−βc/β]2+) to leading order, where a is the scattering length of the two-body interaction potential, ρ is the density, β is the inverse temperature, and βc is the inverse Berezinskii–Kosterlitz–Thouless critical temperature for superfluidity. In combination with the corresponding matching lower bound proved by Deuchert et al. [Forum Math. Sigma 8, e20 (2020)], this shows equality in the asymptotic expansion."}],"corr_author":"1","quality_controlled":"1","date_published":"2020-06-22T00:00:00Z","publication":"Journal of Mathematical Physics","user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","citation":{"ama":"Mayer S, Seiringer R. The free energy of the two-dimensional dilute Bose gas. II. Upper bound. <i>Journal of Mathematical Physics</i>. 2020;61(6). doi:<a href=\"https://doi.org/10.1063/5.0005950\">10.1063/5.0005950</a>","chicago":"Mayer, Simon, and Robert Seiringer. “The Free Energy of the Two-Dimensional Dilute Bose Gas. II. Upper Bound.” <i>Journal of Mathematical Physics</i>. AIP Publishing, 2020. <a href=\"https://doi.org/10.1063/5.0005950\">https://doi.org/10.1063/5.0005950</a>.","ista":"Mayer S, Seiringer R. 2020. The free energy of the two-dimensional dilute Bose gas. II. Upper bound. Journal of Mathematical Physics. 61(6), 061901.","mla":"Mayer, Simon, and Robert Seiringer. “The Free Energy of the Two-Dimensional Dilute Bose Gas. II. Upper Bound.” <i>Journal of Mathematical Physics</i>, vol. 61, no. 6, 061901, AIP Publishing, 2020, doi:<a href=\"https://doi.org/10.1063/5.0005950\">10.1063/5.0005950</a>.","short":"S. Mayer, R. Seiringer, Journal of Mathematical Physics 61 (2020).","apa":"Mayer, S., &#38; Seiringer, R. (2020). The free energy of the two-dimensional dilute Bose gas. II. Upper bound. <i>Journal of Mathematical Physics</i>. AIP Publishing. <a href=\"https://doi.org/10.1063/5.0005950\">https://doi.org/10.1063/5.0005950</a>","ieee":"S. Mayer and R. Seiringer, “The free energy of the two-dimensional dilute Bose gas. II. Upper bound,” <i>Journal of Mathematical Physics</i>, vol. 61, no. 6. AIP Publishing, 2020."},"ec_funded":1,"day":"22","oa_version":"Preprint","publication_status":"published","article_number":"061901","fulldoi":"https://doi.org/10.1063/5.0005950","title":"The free energy of the two-dimensional dilute Bose gas. II. Upper bound","_id":"8134","language":[{"iso":"eng"}],"article_type":"original","doi":"10.1063/5.0005950","project":[{"_id":"25C6DC12-B435-11E9-9278-68D0E5697425","call_identifier":"H2020","grant_number":"694227","name":"Analysis of quantum many-body systems"}],"external_id":{"isi":["000544595100001"],"arxiv":["2002.08281"]},"oa":1,"month":"06","issue":"6","publication_identifier":{"issn":["0022-2488"]},"date_created":"2020-07-19T22:00:59Z","status":"public"}]