2009/02/09 by Stefan Rombouts, Stefan M. A. Rombouts, Rombouts, Stefan M. A.
Economics, Econometrics and Finance · Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Complex Systems and Time Series Analysis #FOS: Physical sciences #Physics of Superconductivity and Magnetism #Strongly Correlated Electrons (cond-mat.str-el) #cond-mat.str-el
paper · pdf · doi:10.48550/arxiv.0902.1450
3 figures
arxiv created 2009/02/09 · openalex publication_date 2009/02/09 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The ground state phase diagram of the two-dimensional attractive Hubbard model with population imbalance is explored using a mean field ansatz. A linear programming algorithm is used to identify the blocked states, such that the population imbalance can be imposed exactly. This allows to explore regions of the number-projected phase diagram that can not be obtained with the conventional Bogoliubov-de Gennes ansatz. The Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) phase of pairs with non-zero momentum is found to be the ground state over a wide range of parameters, while phase separation occurs only in a limited region at small population imbalance. Through a particle-hole transformation these results can be related to the underdoped repulsive Hubbard model, where the FFLO phase takes the form of a particle-hole condensate that exhibits a spontaneous restoration of spin symmetry.