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In this paper we show how the classification of topological phases in insulators and superconductors is changed by interactions, in the case of 1D systems. We focus on the TR-invariant Majorana chain (BDI symmetry class). While the band…

Strongly Correlated Electrons · Physics 2013-05-29 Lukasz Fidkowski , Alexei Kitaev

Examples of non-hermitian quantum systems admitting topological insulator phase are presented in one, two and three space dimensions. All of these non-hermitian Hamiltonians have entirely real bulk eigenvalues and unitarity is maintained…

Quantum Physics · Physics 2012-03-19 Pijush K. Ghosh

Spatially resolved local quantum geometric markers play a crucial role in the diagnosis of topological phases without long-range translational symmetry, including amorphous systems. Here, we focus on the nonlocality of such markers. We…

Mesoscale and Nanoscale Physics · Physics 2025-11-14 Quentin Marsal , Hui Liu , Emil J. Bergholtz , Annica M. Black-Schaffer

We develop the topological band theory for systems described by non-Hermitian Hamiltonians, whose energy spectra are generally complex. After generalizing the notion of gapped band structures to the non-Hermitian case, we classify "gapped"…

Mesoscale and Nanoscale Physics · Physics 2018-04-11 Huitao Shen , Bo Zhen , Liang Fu

We introduce a Hamiltonian for fermions on a lattice and prove a theorem regarding its topological properties. We identify the topological criterion as a $\mathbb{Z}_2-$ topological invariant $p(\textbf{k})$ (the Pfaffian polynomial). The…

Mesoscale and Nanoscale Physics · Physics 2017-05-16 Bruno Mera , Miguel A. N. Araújo , Vítor R. Vieira

Local topological markers, topological invariants evaluated by local expectation values, are valuable for characterizing topological phases in materials lacking translation invariance. The Chern marker -- the Chern number expressed in terms…

Mesoscale and Nanoscale Physics · Physics 2023-01-11 Julia D. Hannukainen , Miguel F. Martinez , Jens H. Bardarson , Thomas Klein Kvorning

Non-Hermitian matrices are ubiquitous in the description of nature ranging from classical dissipative systems, including optical, electrical, and mechanical metamaterials, to scattering of waves and open quantum many-body systems. Seminal…

Mesoscale and Nanoscale Physics · Physics 2024-07-08 Kang Yang , Zhi Li , J. Lukas K. König , Lukas Rødland , Marcus Stålhammar , Emil J. Bergholtz

In the framework of an extended phenomenological approach to phase transitions, it is shown that existing nonlinear relation between local critical atomic parameters and phenomenological order parameter induces the corresponding nonlinear…

Statistical Mechanics · Physics 2015-06-23 Vladimir Dmitriev

In this letter, we investigate topological phases of full-gapped odd-parity superconductors, which are distinguished by the bulk topological invariants and the topologically protected gapless boundary states. Using the particle-hole…

Superconductivity · Physics 2010-10-20 Masatoshi Sato

We proposed a framework for the topological classification of non-Hermitian systems. Different from previous $K$-theoretical approaches, our approach is a homotopy classification, which enables us to see more topological invariants.…

Mesoscale and Nanoscale Physics · Physics 2022-06-09 Zhi Li , Roger S. K. Mong

We review the dimensional reduction procedure in the group cohomology classification of bosonic SPT phases with finite abelian unitary symmetry group. We then extend this to include general reductions of arbitrary dimensions and also extend…

Strongly Correlated Electrons · Physics 2017-11-02 Nathanan Tantivasadakarn

A method of using partial symmetries to distinguish two dimensional symmetry protected topological (SPT) phases of on-site, unitary symmetries is proposed. This novel order parameter takes a wavefunction, such as a ground state of a lattice…

Strongly Correlated Electrons · Physics 2025-07-10 Alex Turzillo , Naren Manjunath , Jose Garre-Rubio

The classification of topological states of matter in terms of unitary symmetries and dimensionality predicts the existence of nontrivial topological states even in zero-dimensional systems, i.e., a system with a discrete energy spectrum.…

Mesoscale and Nanoscale Physics · Physics 2018-06-11 Pasquale Marra , Alessandro Braggio , Roberta Citro

Recently, it was realized that anomalies can be completely classified by topological orders, symmetry protected topological (SPT) orders, and symmetry enriched topological orders in one higher dimension. The anomalies that people used to…

Strongly Correlated Electrons · Physics 2019-11-06 Wenjie Ji , Xiao-Gang Wen

We study the competition of disorder and superconductivity for a one-dimensional p-wave superconductor in incommensurate potentials. With the increase in the strength of the incommensurate potential, the system undergoes a transition from a…

Disordered Systems and Neural Networks · Physics 2015-03-20 Xiaoming Cai , Li-Jun Lang , Shu Chen , Yupeng Wang

Topological superconductors are exotic phases of matter featuring robust surface states that could be leveraged for topological quantum computation. A useful guiding principle for the search of topological superconductors is to relate the…

Superconductivity · Physics 2020-05-05 Seishiro Ono , Hoi Chun Po , Haruki Watanabe

Both theoretical and experimental studies of topological phases in non-Hermitian systems have made a remarkable progress in the last few years of research. In this article, we review the key concepts pertaining to topological phases in…

Mesoscale and Nanoscale Physics · Physics 2019-07-18 Ananya Ghatak , Tanmoy Das

We construct fixed point lattice models for group supercohomology symmetry protected topological (SPT) phases of fermions in 2+1D. A key feature of our approach is to construct finite depth circuits of local unitaries that explicitly build…

Strongly Correlated Electrons · Physics 2019-02-05 Tyler D. Ellison , Lukasz Fidkowski

Symmetry-protected topological (SPT) phases are short-range entangled phases of matter with a non-local order parameter which are preserved under a local symmetry group. Here, by using unsupervised learning algorithm, namely the diffusion…

Strongly Correlated Electrons · Physics 2021-11-18 En-Jui Kuo , Hossein Dehghani

For an anyon model in two spatial dimensions described by a modular tensor category, the topological S-matrix encodes the mutual braiding statistics, the quantum dimensions, and the fusion rules of anyons. It is nontrivial whether one can…

Quantum Physics · Physics 2016-03-04 Jeongwan Haah