Physics (Internal)

Novel topological phenomena in non-equilibrium systems

This event is part of the Condensed Matter Theory Seminar Series.

Abstract
Recent rapid development of experimental technology in cold atoms, quantum optics and condensed matter physics now allows the access to quantum physics in non-equilibrium, which was previously hard to study due to the fast relaxation and limited controls. Motivated by this perspective, we previously classified new topological structures in periodically driven systems and showed that such systems allow 1. to design and engineer static topological properties in a versatile
fashion 2. to induce unique topological phenomena that do not exist in static systems.
In this talk, we discuss various theoretical as well as experimental examples in cold atoms, quantum optics and condensed matter physics, including the observation of zero-energy bound states predicted in Su-Schrieffer-Heeger model, demonstration of the existence of two flavors of Majorana Fermions and non-equilibrium realization of Haldane model through the application of circularly polarized light on graphene.  We further discuss the physical
manifestations of the topological physics through non-equilibrium transport. Such non-equiiibrium realizations provide new paradigm and platforms to study topological phenomena, which are still rare in static systems.

I will provide backgrounds of topological physics at the beginning of the talk to make it accessible to non-specialists.

References:
Observation of topologically protected bound states in a one
dimensional photonic system
T. Kitagawa, M. A. Broome et al. arXiv:1105.5334

Topological characterization of periodically driven systems
T. Kitagawa, et al. Phys. Rev. B 82, 235114 (2010); arXiv:1010.6126

Photo-induced quantum Hall insulators without Landau levels
T. Kitagawa, et al.; arXiv:1104.4636

Majorana Fermions in Equilibrium and Driven Cold Atom Quantum Wires
L. Jiang, T. Kitagawa, et al. Phys. Rev. Lett. 106, 220402 (2011) ;
arXiv:1102.5367