Zhoushen Huang

Topological indices for open and thermal systems via Uhlmann's phase.

Two-dimensional topological phases are characterized by Thouless-Kohmoto-Nightingale-den Nijs integers, which classify Bloch energy bands or groups of Bloch bands. However, quantization does not survive thermal averaging or dephasing to mixed states. We show that using Uhlmanns parallel transport for density matrices [Rep. Math. Phys. 24, 229 (1986).

Dynamical Quantum Phase Transitions : Role of Topological Nodes in Wave Function Overlaps

A sudden quantum quench of a Bloch band from one topological phase toward another has been shown to exhibit an intimate connection with the notion of a dynamical quantum phase transition (DQPT), where the returning probability of the quenched state to the initial state-i.e., the Loschmidt echo-vanishes at critical times {t^{*}}. Analytical results to date are limited to two-band models, leaving the exact relation between topology and DQPT unclear. In this Letter, we show that, for a general multiband system, a robust DQPT relies on the existence of nodes (i.e., zeros) in the wave function overlap between the initial band and the postquench energy eigenstates. These nodes are topologically protected if the two participating wave functions have distinctive topological indices. We demonstrate these ideas in detail for both one and two spatial dimensions using a three-band generalized Hofstadter model. We also discuss possible experimental observations.

Stability of Weyl metals under impurity scattering

We investigate the effects of bulk impurities on the electronic spectrum of Weyl semimetals, a recently identified class of Dirac-type materials. Using a

Entanglement spectrum and Wannier center flow of the Hofstadter problem

T

Fate and remnants of Majorana zero modes in a quantum wire array

-matrix approach, we study resonant scattering due to a localized impurity in tight-binding versions of the continuum models recently discussed by [Burkov, Hook, and Balents, Phys. Rev. B 84, 235126 (2011)], describing perturbed four-component Dirac fermions in the vicinity of a critical point. The impurity potential is described by a strength

Impurity scattering in Weyl semimetals and their stability classification

g

Odd frequency pairing of interacting Majorana fermions

as well as a matrix structure

Invariance of Topological Indices Under Hilbert Space Truncation

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Experimental and theoretical study of topology and electronic correlations in PuB4

. Unlike the case in

Complexity and geometry of quantum state manifolds

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