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Usually $Z_2$ topological insulators are protected by time reversal symmetry. Here, we present a new type of $Z_2$ topological insulators in a cubic lattice which is protected by a novel hidden symmetry, while time reversal symmetry is…

Mesoscale and Nanoscale Physics · Physics 2017-12-07 Jing-Min Hou , Wei Chen

Non-trivial braid-group representations appear as non-Abelian quantum statistics of emergent Majorana zero modes in one and two-dimensional topological superconductors. Here, we generate such representations with topologically protected…

Mesoscale and Nanoscale Physics · Physics 2020-04-08 Yafis Barlas , Emil Prodan

Topological phases of matter are generally characterized by topological properties of energy bands of a system. Their transitions under preserved symmetries occur through closing a gap of energy bands, leading to topologically protected…

Mesoscale and Nanoscale Physics · Physics 2020-04-29 Yan-Bin Yang , Kai Li , Yong Xu

We study a general problem how the gap in a nonmagnetic band insulator closes by tuning a parameter. We review our recent results on the classification of all the possible gap closing in two and three dimensions. We show that they accompany…

Mesoscale and Nanoscale Physics · Physics 2012-01-31 Shuichi Murakami

We lay out an experiment to realize time-reversal invariant topological insulators in alkali atomic gases. We introduce an original method to synthesize a gauge field in the near-field of an atom-chip, which effectively mimics the effects…

The non-Abelian tensor gauge fields take value in extended Poincar\'e algebra. In order to define the invariant Lagrangian we introduce a vector variable in two alternative ways: through the transversal representation of the extended…

High Energy Physics - Theory · Physics 2018-01-17 George Savvidy

We revisit the question of whether a two-dimensional topological insulator may arise in a commensurate N\'eel antiferromagnet, where staggered magnetization breaks both the elementary translation and time reversal, but retains their product…

Strongly Correlated Electrons · Physics 2016-04-07 Frédéric Bègue , Pierre Pujol , Revaz Ramazashvili

Topological phases characterized by non-Abelian charges are beyond the scope of the paradigmatic tenfold way and have gained increasing attention recently. Here we investigate topological insulators with multiple tangled gaps in Floquet…

Mesoscale and Nanoscale Physics · Physics 2023-10-16 Tianyu Li , Haiping Hu

It has been known that an anti-unitary symmetry such as time-reversal or charge conjugation is needed to realize Z2 topological phases in non-interacting systems. Topological insulators and superconducting nanowires are representative…

Mesoscale and Nanoscale Physics · Physics 2015-04-22 Ken Shiozaki , Masatoshi Sato , Kiyonori Gomi

This paper is a survey of the $\mathbb{Z}_2$-valued invariant of topological insulators used in condensed matter physics. The $\mathbb{Z}$-valued topological invariant, which was originally called the TKNN invariant in physics, has now been…

Mathematical Physics · Physics 2016-12-28 Ralph M. Kaufmann , Dan Li , Birgit Wehefritz-Kaufmann

The nontrivial evolution of Wannier functions (WF) for the occupied bands is a good starting point to understand topological insulator. By modifying the definition of WFs from the eigenstates of the projected position operator to those of…

Quantum Gases · Physics 2015-04-24 Ye Xiong , Peiqing Tong

We study a non-Hermitian Rice-Mele model without breaking time-reversal symmetry, with the non-Hermiticity arising from imbalanced hopping rates. The Berry connection, Berry curvature and Chern number are introduced in the context of…

Quantum Physics · Physics 2018-10-24 R. Wang , X. Z. Zhang , Z. Song

Topological insulators, along with Chern insulators and Quantum Hall insulator phases, are considered as paradigms for symmetry protected topological phases of matter. This article reports the experimental realization of the time-reversal…

Mesoscale and Nanoscale Physics · Physics 2021-01-01 Priya Tiwari , Saurabh Kumar Srivastav , Sujay Ray , Tanmoy Das , Aveek Bid

We revisit the problem of classifying topological band structures in non-Hermitian systems. Recently, a solution has been proposed, which is based on redefining the notion of energy band gap in two different ways, leading to the so-called…

Mathematical Physics · Physics 2020-05-20 Charles C. Wojcik , Xiao-Qi Sun , Tomáš Bzdušek , Shanhui Fan

We study the braiding statistics of particle-like and loop-like excitations in 2D and 3D gauge theories with finite, Abelian gauge group. The gauge theories that we consider are obtained by gauging the symmetry of gapped, short-range…

Strongly Correlated Electrons · Physics 2015-04-20 Chenjie Wang , Michael Levin

We propose an experimental scheme to simulate and detect the properties of time-reversal invariant topological insulators, using cold atoms trapped in one-dimensional bichromatic optical lattices. This system is described by a…

Quantum Gases · Physics 2012-01-30 Feng Mei , Shi-Liang Zhu , Zhi-Ming Zhang , C. H. Oh , N. Goldman

Symmetries play an essential role in identifying and characterizing topological states of matter. Here, we classify topologically two-dimensional (2D) insulators and semimetals with vanishing spin-orbit coupling using time-reversal…

Mesoscale and Nanoscale Physics · Physics 2016-12-14 Guido van Miert , Carmine Ortix , Cristiane Morais Smith

Twisted bilayer MoTe$_2$ near two-degree twists has emerged as a platform for exotic correlated topological phases, including ferromagnetism and a non-Abelian fractional spin Hall insulator. Here we reveal the unexpected emergence of an…

Strongly Correlated Electrons · Physics 2026-03-16 Cheong-Eung Ahn , Donghae Seo , Gyeoul Lee , Youngwook Kim , Gil Young Cho

The interface between a superconductor and a topological insulator has been proposed to harbor novel quasiparticles that realize physical schemes for fault-tolerant quantum computation. Here, we present high resolution angle-resolved…

Mesoscale and Nanoscale Physics · Physics 2009-10-08 Y. Xia , L. Wray , D. Qian , D. Hsieh , A. Pal , H. Lin , A. Bansil , D. Grauer , Y. S. Hor , R. J. Cava , M. Z. Hasan

Following the centuries old concept of the quantization of flux through a Gaussian curvature (Euler characteristic) and its successive dispersal into various condensed matter properties such as quantum Hall effect, and topological…

Mesoscale and Nanoscale Physics · Physics 2018-10-23 Tanmoy Das