A lower bound for the BCS functional with boundary conditions at infinity Deuchert, Andreas ; https://orcid.org/0000-0003-3146-6746 We consider a many-body system of fermionic atoms interacting via a local pair potential and subject to an external potential within the framework of Bardeen-Cooper-Schrieffer (BCS) theory. We measure the free energy of the whole sample with respect to the free energy of a reference state which allows us to define a BCS functional with boundary conditions at infinity. Our main result is a lower bound for this energy functional in terms of expressions that typically appear in Ginzburg-Landau functionals. AIP Publishing 2017 info:eu-repo/semantics/article doc-type:article article http://purl.org/coar/resource_type/c_2df8fbb1 https://research-explorer.ista.ac.at/record/912 Deuchert A. A lower bound for the BCS functional with boundary conditions at infinity. <i>Journal of Mathematical Physics</i>. 2017;58(8). doi:<a href="https://doi.org/10.1063/1.4996580">10.1063/1.4996580</a> eng info:eu-repo/semantics/altIdentifier/doi/10.1063/1.4996580 info:eu-repo/semantics/altIdentifier/issn/0022-2488 info:eu-repo/semantics/altIdentifier/wos/000409197200015 info:eu-repo/semantics/altIdentifier/arxiv/1703.04616 info:eu-repo/semantics/openAccess