title: Comment on "Exploring chaos in the Dicke model using ground-state fidelity and Loschmidt echo".
abstract: In a recent paper [Phys. Rev. E 90, 022920 (2014)] a study of the ground-state fidelity of the Dicke model as a function of the coupling parameter is presented. Abrupt jumps of the fidelity in the superradiant phase are observed and are assumed to be related to the transition to chaos. We show that this conclusion results from a misinterpretation of the numerics. In fact, if the parity symmetry is taken into account, the unexpected jumps disappear.
authors: Instituto de Investigaciones Físicas de Mar del Plata (IFIMAR, CONICET), Universidad Nacional de Mar del Plata, Mar del Plata, Argentina.|Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Argentina.
authors: Ignacio
authors: I
authors: García-Mata
authors: Departamento de Física "J. J. Giambiagi," and IFIBA, FCEyN, Universidad de Buenos Aires, 1428 Buenos Aires, Argentina.
authors: Augusto J
authors: AJ
authors: Roncaglia
authors: Departamento de Física "J. J. Giambiagi," and IFIBA, FCEyN, Universidad de Buenos Aires, 1428 Buenos Aires, Argentina.
authors: Diego A
authors: DA
authors: Wisniacki