Wang, QianPérez Bernal, Francisco2022-02-182022-02-182021Wang, Q., & Pérez-Bernal, F. (2021). Signatures of excited-state quantum phase transitions in quantum many-body systems: Phase space analysis. In Physical Review E (Vol. 104, Issue 3). American Physical Society (APS). https://doi.org/10.1103/physreve.104.0341192470-00452470-0053 (electrónico)http://hdl.handle.net/10272/20614Using the Husimi quasiprobability distribution, we investigate the phase space signatures of excited-state quantum phase transitions (ESQPTs) in the Lipkin-Meshkov-Glick and coupled top models. We show that the ESQPT is evinced by the dynamics of the Husimi function, that exhibits a distinct time dependence in the different ESQPT phases. We also discuss how to identify the ESQPT signatures from the long-time averaged Husimi function and its associated marginal distributions. Moreover, from the calculated second moment and Wherl entropy of the long-time averaged Husimi function, we estimate the critical points of the ESQPT in both models, obtaining a good agreement with analytical (mean field) results. We provide a firm evidence that phase space methods are both a new probe for the detection and a valuable tool for the study of ESQPTs.engAtribución-NoComercial-SinDerivadas 3.0 Españahttp://creativecommons.org/licenses/by-nc-nd/3.0/es/journal article10.1103/physreve.104.034119open access22 Física