Topological phases, Majorana modes and quench dynamics in a spin ladder system

DeGottardi, Wade and Sen, Diptiman and Vishveshwara, Smitha (2011) Topological phases, Majorana modes and quench dynamics in a spin ladder system. In: New Journal of Physics, 13 .

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Abstract

We explore the salient features of the `Kitaev ladder', a two-legged ladder version of the spin-1/2 Kitaev model on a honeycomb lattice, by mapping it to a one-dimensional fermionic p-wave superconducting system. We examine the connections between spin phases and topologically non-trivial phases of non-interacting fermionic systems, demonstrating the equivalence between the spontaneous breaking of global Z(2) symmetry in spin systems and the existence of isolated Majorana modes. In the Kitaev ladder, we investigate topological properties of the system in different sectors characterized by the presence or absence of a vortex in each plaquette of the ladder. We show that vortex patterns can yield a rich parameter space for tuning into topologically non-trivial phases. We introduce and employ a new topological invariant for explicitly determining the presence of zero energy Majorana modes at the boundaries of such phases. Finally, we discuss dynamic quenching between topologically non-trivial phases in the Kitaev ladder and, in particular, the post-quench dynamics governed by tuning through a quantum critical point.

Item Type:	Journal Article
Publication:	New Journal of Physics
Publisher:	IOP Publishing ltd
Additional Information:	Copyright of this article belongs to IOP Publishing ltd.
Department/Centre:	Division of Physical & Mathematical Sciences > Centre for High Energy Physics
Date Deposited:	18 Jul 2011 08:30
Last Modified:	18 Jul 2011 08:30
URI:	http://eprints.iisc.ac.in/id/eprint/39088

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