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We study the quantum metric tensor and its scalar curvature for a particular version of the Lipkin-Meshkov-Glick model. We build the classical Hamiltonian using Bloch coherent states and find its stationary points. They exhibit the presence…

We investigate the quantum metric and topological Euler number in a cyclically modulated Su-Schrieffer-Heeger (SSH) model with long-range hopping terms. By computing the quantum geometry tensor, we derive exactly expressions for the quantum…

Strongly Correlated Electrons · Physics 2024-04-15 Xiang-Long Zeng , Wen-Xi Lai , Yi-Wen Wei , Yu-Quan Ma

Holographic quantum error-correcting codes have been proposed as toy models that describe key aspects of the AdS/CFT correspondence. In this work, we introduce a versatile framework of Majorana dimers capturing the intersection of…

High Energy Physics - Theory · Physics 2019-11-12 Alexander Jahn , Marek Gluza , Fernando Pastawski , Jens Eisert

Supersymmetric quantum mechanical models are computed by the Path integral approach. In the $\beta\rightarrow0$ limit, the integrals localize to the zero modes. This allows us to perform the index computations exactly because of…

High Energy Physics - Theory · Physics 2016-03-31 Muhammad Abdul Wasay

Although topological band theory has been used to discover and classify a wide array of novel topological phases in insulating and semi-metal systems, it is not well-suited to identifying topological phenomena in metallic or gapless…

Mesoscale and Nanoscale Physics · Physics 2022-09-13 Alexander Cerjan , Terry A. Loring

Twisting bilayers of two-dimensional topological insulators has the potential to create unique quantum states of matter. Here, we successfully synthesized a twisted bilayer of germanene on Ge2Pt(101) with a 21.8$^o$ degrees twist angle,…

One-dimensional superlattices with modulated coupling constants show rich topological properties and tunable edge states. Beyond the dimeric case, probing the topological properties of superlattices is a challenge. Here we suggest a rather…

Optics · Physics 2020-12-15 Stefano Longhi

The discovery of the quantised Hall effect, and its subsequent topological explanation, demonstrated the important role topology can play in determining the properties of quantum systems. This realisation led to the development of…

The explicit construction of non-dispersive flat band modes and the tunability of has been reported for a hierarchical 3-simplex fractal geometry. A single band tight binding Hamiltonian defined for the deterministic self-similar…

Mesoscale and Nanoscale Physics · Physics 2021-02-08 Atanu Nandy

We develop two connections between the quantitative framework of operator $K$-theory for geometric $C^*$-algebras and the problem of positive scalar curvature. First, we introduce a quantitative notion of higher index and use it to give a…

K-Theory and Homology · Mathematics 2024-09-02 Hao Guo , Zhizhang Xie , Guoliang Yu

The quantum metric is a fundamental ingredient of band quantum geometry and has recently at tracted intense interest, with most of its transport signatures appearing in the intrinsic second order nonlinear conductivity. In the clean limit,…

Disordered Systems and Neural Networks · Physics 2026-04-23 Bo Yin , Zhijun Wang , Quansheng Wu

The recent discovery of Dirac semimetals represents a new achievement in our fundamental understanding of topological states of matter. Due to their topological surface states, high mobility, and exotic properties associated with bulk Dirac…

Mesoscale and Nanoscale Physics · Physics 2015-02-13 Xianbo Xiao , Shengyuan A. Yang , Zhengfang Liu , Huili Li , Guanghui Zhou

Recent theories and experiments have suggested that strong spin-orbit coupling effects in certain band insulators can give rise to a new phase of quantum matter, the so-called topological insulator, which can show macroscopic entanglement…

Mesoscale and Nanoscale Physics · Physics 2009-08-26 Y. Xia , D. Qian , D. Hsieh , L. Wray , A. Pal , H. Lin , A. Bansil , D. Grauer , Y. S. Hor , R. J. Cava , M. Z. Hasan

We investigate quantum tunneling of charge carriers through a periodic superlattice in twisted bilayer graphene (TBG) with rectangular potential barriers, including the presence of a defect, using a low-energy continuum model. Transmission…

Mesoscale and Nanoscale Physics · Physics 2026-01-08 Ayoub Bahlaoui , Youness Zahidi , Ahmed Naddami

The quantum metric -- which quantifies the distance between quantum states -- is a fundamental component of the quantum geometric tensor, playing a crucial role in a wide range of physical phenomena. Its direct detection and control remains…

Mesoscale and Nanoscale Physics · Physics 2025-12-02 Md Afsar Reja , Arka Bandyopadhyay , Awadhesh Narayan

The importance of controlling both the charge carrier density and the band gap of a semiconductor cannot be overstated, as it opens the doors to a wide range of applications, including, e.g., highly-tunable transistors, photodetectors, and…

We develop a diagrammatic perturbation theory to account for the emergence of moir\'e bands in the continuum model of twisted bilayer graphene. Our framework is build upon treating the moir\'e potential as a perturbation that transfers…

Mesoscale and Nanoscale Physics · Physics 2024-07-30 Federico Escudero

We propose to realize Dirac states in an inclined two-dimensional Su-Schrieffer-Heeger model on a square lattice. We show that a pair of Dirac points protected by space-time inversion symmetry appear in the semimetal phase. The locations of…

Mesoscale and Nanoscale Physics · Physics 2022-06-07 Chang-An Li , Sang-Jun Choi , Song-Bo Zhang , Björn Trauzettel

Measurement plays a quintessential role in the control of quantum systems. Beyond initialization and readout which pertain to projective measurements, weak measurements in particular, through their back-action on the system, may enable…

Quantum Physics · Physics 2022-06-07 Yunzhao Wang , Kyrylo Snizhko , Alessandro Romito , Yuval Gefen , Kater Murch

The band structure and transport properties of massive Dirac Fermions in bilayer graphene with velocity modulation in space are investigated in presence of the previously created band gap. It is pointed out that the velocity engineering is…

Mesoscale and Nanoscale Physics · Physics 2013-11-27 Hosein Cheraghchi , Fatemeh Adinehvand