Heidelberg 2015 – scientific programme
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A: Fachverband Atomphysik
A 41: Ultra-cold atoms, ions and BEC V (with Q)
A 41.6: Talk
Friday, March 27, 2015, 12:15–12:30, M/HS1
Critical quasienergy states in driven many-body systems — Victor Manuel Bastidas1, •Georg Engelhardt1, Pedro Pérez-Fernández2, Malte Vogl3, and Tobias Brandes1 — 1Institut für Theoretische Physik, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin, Germany — 2Departamento de Física Aplicada III, Escuela Superior de Ingeniería, Universidad de Sevilla, Camino de los Descubrimientos s/n, ES-41092 Sevilla, Spain — 3Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Straße 38, 01187 Dresden, Germany
We discuss singularities in the spectrum of driven many-body spin systems. In contrast to undriven models, the driving allows us to control the geometry of the quasienergy landscape. As a consequence, one can engineer singularities in the density of quasienergy states by tuning an external control. We show that the density of levels exhibits logarithmic divergences at the saddle points, while jumps are due to local minima of the quasienergy landscape. We discuss the characteristic signatures of these divergences in observables like the magnetization, which should be measurable with current technology [1].
[1] V.M. Bastidas, G. Engelhardt, P. Pérez-Fernández, M. Vogl, and T. Brandes. arXiv:1410.5281 (To appear in Phys. Rev. A)