{"oa_version":"Submitted Version","abstract":[{"text":"We study translation-invariant quasi-free states for a system of fermions with two-particle interactions. The associated energy functional is similar to the BCS functional but also includes direct and exchange energies. We show that for suitable short-range interactions, these latter terms only lead to a renormalization of the chemical potential, with the usual properties of the BCS functional left unchanged. Our analysis thus represents a rigorous justification of part of the BCS approximation. We give bounds on the critical temperature below which the system displays superfluidity.","lang":"eng"}],"publisher":"World Scientific Publishing","user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","oa":1,"external_id":{"arxiv":["1305.5135"]},"date_updated":"2022-06-07T09:03:09Z","day":"01","language":[{"iso":"eng"}],"year":"2014","main_file_link":[{"open_access":"1","url":"http://arxiv.org/abs/1305.5135"}],"publist_id":"5206","article_type":"original","intvolume":"        26","publication":"Reviews in Mathematical Physics","doi":"10.1142/S0129055X14500123","title":"Translation-invariant quasi-free states for fermionic systems and the BCS approximation","date_published":"2014-08-01T00:00:00Z","acknowledgement":"We would like to thank Max Lein and Andreas Deuchert for valuable suggestions and remarks. Partial financial support by the NSERC (R.S.) is gratefully acknowledged.","date_created":"2018-12-11T11:54:33Z","scopus_import":"1","article_number":"1450012","month":"08","author":[{"last_name":"Bräunlich","first_name":"Gerhard","full_name":"Bräunlich, Gerhard"},{"full_name":"Hainzl, Christian","last_name":"Hainzl","first_name":"Christian"},{"full_name":"Seiringer, Robert","last_name":"Seiringer","first_name":"Robert","id":"4AFD0470-F248-11E8-B48F-1D18A9856A87","orcid":"0000-0002-6781-0521"}],"citation":{"ama":"Bräunlich G, Hainzl C, Seiringer R. Translation-invariant quasi-free states for fermionic systems and the BCS approximation. <i>Reviews in Mathematical Physics</i>. 2014;26(7). doi:<a href=\"https://doi.org/10.1142/S0129055X14500123\">10.1142/S0129055X14500123</a>","chicago":"Bräunlich, Gerhard, Christian Hainzl, and Robert Seiringer. “Translation-Invariant Quasi-Free States for Fermionic Systems and the BCS Approximation.” <i>Reviews in Mathematical Physics</i>. World Scientific Publishing, 2014. <a href=\"https://doi.org/10.1142/S0129055X14500123\">https://doi.org/10.1142/S0129055X14500123</a>.","apa":"Bräunlich, G., Hainzl, C., &#38; Seiringer, R. (2014). Translation-invariant quasi-free states for fermionic systems and the BCS approximation. <i>Reviews in Mathematical Physics</i>. World Scientific Publishing. <a href=\"https://doi.org/10.1142/S0129055X14500123\">https://doi.org/10.1142/S0129055X14500123</a>","mla":"Bräunlich, Gerhard, et al. “Translation-Invariant Quasi-Free States for Fermionic Systems and the BCS Approximation.” <i>Reviews in Mathematical Physics</i>, vol. 26, no. 7, 1450012, World Scientific Publishing, 2014, doi:<a href=\"https://doi.org/10.1142/S0129055X14500123\">10.1142/S0129055X14500123</a>.","ista":"Bräunlich G, Hainzl C, Seiringer R. 2014. Translation-invariant quasi-free states for fermionic systems and the BCS approximation. Reviews in Mathematical Physics. 26(7), 1450012.","ieee":"G. Bräunlich, C. Hainzl, and R. Seiringer, “Translation-invariant quasi-free states for fermionic systems and the BCS approximation,” <i>Reviews in Mathematical Physics</i>, vol. 26, no. 7. World Scientific Publishing, 2014.","short":"G. Bräunlich, C. Hainzl, R. Seiringer, Reviews in Mathematical Physics 26 (2014)."},"status":"public","_id":"1889","quality_controlled":"1","publication_status":"published","volume":26,"department":[{"_id":"RoSe"}],"issue":"7","type":"journal_article","article_processing_charge":"No"}