AC-driven Quantum Phase Transitions in spin systems

Datum

04.07.2013

Zeit

14:00 - 15:00

Sprecher

Victor Bastidas

Zugehörigkeit

Technische Universität Berlin

Sprache

en

Hauptthema

Physik

Andere Themen

Physik

Host

Condensed Matter Seminar

Beschreibung

The current feasibilities to control and simulate quantum many-body systems allow to experimentally explore the dynamics of spin systems under the effect of an external driving [1,2]. In this talk I will discuss the Ising and Wen-plaquette (WP) models under the effect of a monochromatic transverse field. In the absence of driving, the transverse Ising model undergoes a transition from the paramagnetic phase to the ferromagnetic phase. We show that the external control induces a set of anisotropic quantum phase transitions, which are absent in the undriven model [3,4]. The undriven WP model is closely related to the toric code of Kitaev [5], and exhibits a transition for a spin-polarized phase to a topologically-ordered phase [6,7]. Similarly to the undriven WP model, we use nonlocal spin-duality transformations to describe a driven transverse WP model in terms of the Ising model physics [6,7]. Interestingly, under the effect of a nonadiabatic monochromatic driving, the system exhibits a new topological phase. The topological character of the WPM requires a description of the QPT in terms of nonlocal order parameters, which correspond to long-range correlation functions for a driven Ising model in the dual picture [8]. [1] M. C. Rechtsman, J. M. Zeuner, Y. Plotnik, Y. Lumer, D. Podolsky, F. Dreisow, S. Nolte, M. Segev, and A. Szameit, Nature {\bf 496} 196 (2013) [2] H. Weimer, M. M\"uller, I. Lesanovsky, P. Zoller, and H. P. B\"uchler, Nature Phys. {\bf 6}, 382 (2010). [3] V. M. Bastidas, C. Emary, G. Schaller, and T. Brandes, Phys. Rev. A {\bf 86},063627 (2012) [4] A. Das, Phys. Rev. B {\bf 82}, 172402 (2010) . [5] A. Yu. Kitaev, Ann. Phys. (NY) {\bf 303}, 2 (2003). [6] X.-G. Wen, Phys. Rev. D {\bf 68}, 065003 (2003). [7] J. Yu, S.-P. Kou, and X.-G. Wen, Europhys. Lett. {\bf 84}, 17004 (2008). [8] V. M. Bastidas, C. Emary, G. Schaller, A. G\'omez-Le\'on, G. Platero, and T.Brandes, arXiv:1302.0781

Letztmalig verändert: 04.07.2013, 10:03:14