Article
Materials Science, Multidisciplinary
Gero von Gersdorff, Shahram Panahiyan, Wei Chen
Summary: This article introduces a unified approach to obtain topological invariants in arbitrary dimensions and symmetry classes by introducing a wrapping number for topological materials described by Dirac models. This method is gauge-invariant, originates from the intrinsic features of the Dirac model, and places all known topological invariants on equal footing.
Article
Chemistry, Multidisciplinary
Peng Li, Jinjun Ding, Steven S-L Zhang, James Kally, Timothy Pillsbury, Olle G. Heinonen, Gaurab Rimal, Chong Bi, August DeMann, Stuart B. Field, Weigang Wang, Jinke Tang, Jidong Samuel Jiang, Axel Hoffmann, Nitin Samarth, Mingzhong Wu
Summary: This study reports a genuine topological Hall effect in a TI/MI structure, where the contribution of skyrmions to the Hall effect outweighs the coexistence of magnetic phases.
Article
Physics, Multidisciplinary
Ruochen Ma, Chong Wang
Summary: In this study, we demonstrate that symmetry-protected topological (SPT) phases can also be applied to average symmetries, where local quenched disorders break the symmetries but restore them upon disorder averaging. We classify and characterize a large class of average SPT phases using a decorated domain wall approach, and show that the boundary states of such phases will almost certainly be long-range entangled. We also develop a theory for generalized average SPT phases based on density matrices and quantum channels, indicating that topological quantum phenomena associated with average symmetries can be as rich as those with exact symmetries.
Article
Multidisciplinary Sciences
Qinghua Guo, Tianshu Jiang, Ruo-Yang Zhang, Lei Zhang, Zhao-Qing Zhang, Biao Yang, Shuang Zhang, C. T. Chan
Summary: Experimental observation of non-Abelian topological charges and edge states in a PT-symmetric transmission line network, along with the discovery of a non-Abelian quotient relation for the bulk-edge correspondence. This new topological property opens up possibilities for intriguing observable phenomena in the field of material science.
Article
Physics, Multidisciplinary
Y. X. Zhao, Cong Chen, Xian-Lei Sheng, Shengyuan A. Yang
Summary: The study reveals the possibility of switching the two fundamental classes via Z(2) projective representations, allowing for unique topological phases to be achieved in different classes. For PT symmetry, the occurrence of this switching mechanism is demonstrated when P inverses the gauge transformation required to recover the original Z(2) gauge connections under P.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Yafei Ren, Cong Xiao, Daniyar Saparov, Qian Niu
Summary: The study investigates the adiabatic evolution of electronic states induced by the lattice vibration of a chiral phonon, obtaining electronic orbital magnetization in the form of a topological second Chern form. The traditional theory needs refinement by introducing a k-resolved Born effective charge and accounting for the phonon-modified electronic energy and momentum-space Berry curvature contribution. The second Chern form may diverge when a Yang's monopole is near the parameter space of interest, as demonstrated in a gapped graphene model at the Brillouin zone corner.
PHYSICAL REVIEW LETTERS
(2021)
Review
Mathematics, Applied
Mark J. Ablowitz, Justin T. Cole
Summary: In recent years, the study of wave propagation in nonlinear photonic lattices has attracted considerable interest. This review article focuses on the propagation of wave envelopes in periodic lattices associated with additional potential in the nonlinear Schrodinger equation. The tight-binding approximation is used to find the linear dispersion relation and the equations governing nonlinear discrete envelopes, and continuous envelope equations are derived from the discrete system in the limit of slowly varying envelopes. The article also explores the potential realization of topological insulator systems in an optical waveguide setting.
PHYSICA D-NONLINEAR PHENOMENA
(2022)
Article
Materials Science, Multidisciplinary
Wei Chen
Summary: We propose a universal topological marker that can map the topological order to lattice sites for topological insulators and superconductors with Dirac models in any dimension and symmetry class. By introducing a topological operator derived from a momentum-space universal topological invariant, we construct the topological marker by alternating projectors, position operators, and Dirac matrices. The off-diagonal elements of the topological operator yield a non-local topological marker, representing a Wannier state correlation function, which decays with a diverging correlation length at topological phase transitions. Various prototype examples are employed to demonstrate the universality of our formalism.
Article
Astronomy & Astrophysics
A. Yu Loginov
Summary: This study investigates the scattering of Dirac fermions in the background fields of topological solitons of the (2 + 1)-dimensional nonlinear O(3) sigma-model using analytical and numerical methods. General formulas describing fermion scattering and the symmetry properties of the S-matrix elements are obtained. The scattering amplitudes, cross sections, and symmetry properties in the Born approximation are analyzed, as well as the numerical dependencies of the S-matrix elements on fermion momentum.
Article
Materials Science, Multidisciplinary
Xun-Jiang Luo, Xiao-Hong Pan, Xin Liu
Summary: The study demonstrates that the interplay between superconductors and magnetic fields based on the surface states of a weak topological insulator can lead to various helical or chiral Majorana hinge modes and even corner modes. The obtained higher-order topological superconductors can naturally behave as a TSC in DIII or D symmetry class due to their certain boundaries, surfaces, or hinges. These higher-order TSCs can be characterized by boundary topological invariants, such as surface Chern numbers or surface Z(2) topological invariants for surface TSCs.
Article
Multidisciplinary Sciences
Rajesh K. Malla, Wilton J. M. Kort-Kamp
Summary: We investigate the dynamics of spin-orbit coupled graphene family materials to unveil topological phase transition fingerprints embedded in the nonlinear regime. Our findings show how these signatures manifest in the nonlinear Kerr effect and in third-harmonic generation processes, shedding light on the unique processes involved in harmonic generation via topological phenomena.
SCIENTIFIC REPORTS
(2021)
Article
Physics, Multidisciplinary
Ari M. Turner, Erez Berg, Ady Stern
Summary: In this study, the stability of fragile topological bands protected by space-time inversion symmetry under strong electron-electron interactions is investigated. It is found that when these fragile bands are half filled, interactions can open a gap in the many-body spectrum without breaking any symmetry or mixing degrees of freedom from remote bands. The resulting ground state is not topologically ordered. The formation of fermionic bound states known as trions is crucial for this result, which may be relevant to recent experiments in magic angle twisted bilayer graphene at charge neutrality.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Daniel Failde, Daniel Baldomir
Summary: In relativistic quantum formalism, second-order corrections due to magnetic fields in two-dimensional topological and Chern insulators play a crucial role in determining the zero-field diamagnetic susceptibility of non-zero Berry curvature systems. These corrections become relevant at relatively low fields and unveil additional contributions from the magnetic field.
NEW JOURNAL OF PHYSICS
(2021)
Article
Materials Science, Multidisciplinary
Sanjib Kumar Das, Bitan Roy
Summary: Bulk dislocation lattice defects are crucial for studying translationally active topological insulators. These defects can lead to the presence of gapless modes under certain conditions. Through the time evolution of density matrices, we find that the signatures of dislocation modes persist for a long time even when entering a phase without gapless modes. Furthermore, when transitioning from a translationally inert insulator to a topological insulator, the signature of the dislocation mode dynamically builds up near its core.
Article
Physics, Multidisciplinary
Matheus I. N. Rosa, Massimo Ruzzene, Emil Prodan
Summary: Twisted bilayered systems exhibit higher dimensional topological phases and 4D integer quantum Hall effect, which can be accessed by sliding the layers relative to each other.
COMMUNICATIONS PHYSICS
(2021)
Article
Physics, Multidisciplinary
Changhua Bao, Hongyun Zhang, Teng Zhang, Xi Wu, Laipeng Luo, Shaohua Zhou, Qian Li, Yanhui Hou, Wei Yao, Liwei Liu, Pu Yu, Jia Li, Wenhui Duan, Hong Yao, Yeliang Wang, Shuyun Zhou
Summary: Researchers have reported direct experimental evidence of chiral symmetry breaking (CSB) in Li-intercalated graphene, showing gap opening at the Dirac point, Kekule-O type modulation, and chirality mixing near the gap edge. This work opens up opportunities for investigating CSB related physics in a Kekule-ordered graphene.
PHYSICAL REVIEW LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Kevin S. Huang, Zhaoyu Han, Steven A. Kivelson, Hong Yao
Summary: In this study, a density-matrix renormalization-group study was conducted on PDW superconducting states on long triangular cylinders, revealing strong quasi-long-range PDW order, divergent PDW susceptibility, and the spontaneous breaking of time-reversal and inversion symmetries. The state was identified as valley-polarized and the PDW was found to arise from intra-pocket pairing with an incommensurate center of mass momentum. This study also observed an unusual realization of a Luther-Emery liquid in the two-leg case.
NPJ QUANTUM MATERIALS
(2022)
Article
Physics, Multidisciplinary
Shi-Xin Zhang, Zhou-Quan Wan, Chee-Kong Lee, Chang-Yu Hsieh, Shengyu Zhang, Hong Yao
Summary: The variational quantum-neural hybrid eigensolver (VQNHE) is introduced in this study, which enhances the shallow-circuit quantum Ansatz by combining classical post-processing with neural networks. Experimental results show that VQNHE consistently outperforms VQE in simulating ground-state energies of quantum spins and molecules, and it represents the first scalable method to exponentially accelerate VQE with nonunitary postprocessing efficiently implemented in the NISQ era.
PHYSICAL REVIEW LETTERS
(2022)
Article
Quantum Science & Technology
Shi-Xin Zhang, Chang-Yu Hsieh, Shengyu Zhang, Hong Yao
Summary: Quantum architecture search (QAS) automates the process of engineering quantum circuits and aims to construct a powerful and general platform that can accelerate the identification of quantum advantages. In this paper, we propose a general framework of differentiable quantum architecture search (DQAS) and demonstrate its capabilities in various circuit design problems. These results highlight the potential of DQAS as a valuable tool for NISQ application developments and present an interesting research topic from a theoretical perspective.
QUANTUM SCIENCE AND TECHNOLOGY
(2022)
Article
Physics, Multidisciplinary
Jin-Tao Jin, Kun Jiang, Hong Yao, Yi Zhou
Summary: This study demonstrates that spontaneous time-reversal symmetry breaking can arise naturally from the interaction between pair density wave ordering at multiple momenta and nesting of Fermi surfaces. The results have important implications for future experiments and real materials such as CsV3Sb5.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Shuo Liu, Shi-Xin Zhang, Chang-Yu Hsieh, Shengyu Zhang, Hong Yao
Summary: In this letter, a simple disorder-free periodically driven model is proposed that exhibits nontrivial discrete time crystal (DTC) order stabilized by Stark many-body localization (MBL). The existence of the DTC phase is demonstrated through analytical analysis and numerical evidence. This new DTC model opens up a new promising avenue for experiments and deepens our understanding of DTCs.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Multidisciplinary
Yi-Ming Wu, Zhengzhi Wu, Hong Yao
Summary: In this paper, we theoretically explore the possible orders induced by weak repulsive interactions in twisted bilayer transition metal dichalcogenides (e.g., WSe2) under an out-of-plane electric field. Our renormalization group analysis shows that superconductivity can survive even with the presence of conventional van Hove singularities. We find that topological chiral superconducting states with different Chern numbers appear over a large parameter region with a moiré filling factor around 1.
PHYSICAL REVIEW LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Shuo Liu, Shi-Xin Zhang, Chang -Yu Hsieh, Shengyu Zhang, Hong Yao
Summary: This study proposes a systematic approach to probe MBL phases using the excited-state variational quantum eigensolver (VQE) and demonstrates convincing results of MBL on a quantum hardware, paving a promising way for future simulations of nonequilibrium systems beyond classical computations in the noisy intermediate-scale quantum (NISQ) era.
Article
Physics, Multidisciplinary
Ming-Rui Li, Ai -Lei He, Hong Yao
Summary: This study proposes a twisted bilayer structure composed of 2D systems and investigates its stable quadratic-band-touching points and exotic physics. The research reveals that exactly flat bands can emerge at specific magic angles with high Chern numbers. Moreover, the effect of Coulomb interactions is considered, and the ground state supports the quantum anomalous Hall effect.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Materials Science, Multidisciplinary
Zhou-Quan Wan, Shi-Xin Zhang, Hong Yao
Summary: As an unbiased method, the quantum Monte Carlo (QMC) method is important for simulating interacting quantum systems. However, it often suffers from the sign problem, which can be mitigated by finding better simulation schemes. In this study, researchers propose a general framework called automatic differentiable sign optimization (ADSO) to automatically search for the best QMC scheme within a given ansatz of the Hubbard-Stratonovich transformation. They apply ADSO to the honeycomb lattice Hubbard model with Rashba spin-orbit coupling and demonstrate its effectiveness in mitigating and even solving the sign problem.
Article
Materials Science, Multidisciplinary
Xun Cai, Zi-Xiang Li, Hong Yao
Summary: This article investigates the Su-Schrieffer-Heeger-Hubbard model and shows that Hubbard interactions can further enhance EPC-induced AFM effects, especially for small phonon frequencies or in adiabatic limit.
Article
Physics, Multidisciplinary
Xiaoyang Shen, Zhengzhi Wu, Linhao Li, Zhehan Qin, Hong Yao
Summary: This Letter investigates the fracton topological order of higher dimensional fracton models at nonzero critical temperature T-c, and demonstrates the existence of a finite critical temperature T-c. By analyzing the free energy of a typical 4D X-cube model using duality, it is shown that a finite critical temperature T-c exists. The expectation value of the 't Hooft loops in the 4D X-cube model reveals a confinement-deconfinement phase transition at finite temperature. Additionally, an alternative no-go theorem for finite-temperature quantum fracton topological order is proposed.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Materials Science, Multidisciplinary
Z. X. Yin, X. Du, W. Z. Cao, J. Jiang, C. Chen, S. R. Duan, J. S. Zhou, X. Gu, R. Z. Xu, Q. Q. Zhang, W. X. Zhao, Y. D. Li, Yi-feng Yang, H. F. Yang, A. J. Liang, Z. K. Liu, H. Yao, Y. P. Qi, Y. L. Chen, L. X. Yang
Summary: This study systematically investigates the electronic structure of the archetypical valence fluctuating compound EuNi2P2, which hosts multiple f electrons, using high-resolution angle-resolved photoemission spectroscopy. The hybridization between Eu 4 f and Ni 3d states is revealed at low temperatures. Interestingly, opposite temperature evolution of electron spectral function above and below the Kondo coherence temperature is observed, which is in contrast to the monotonic valence change and beyond the expectation of the periodic Anderson model.
Article
Materials Science, Multidisciplinary
Ai-Lei He, Wei-Wei Luo, Yuan Zhou, Yi-Fei Wang, Hong Yao
Summary: In this study, two types of topological states are observed in an extended 2D dimerized lattice with staggered flux threading. At 1/2 filling, isolated corner states and metallic near-edge states are observed in the C = 2 Chern insulator states. At 1/4 filling, a C = 0 topological state is found, where the robust edge states are well localized along the edges but bypass corners. These topological insulator states differ from both conventional Chern insulators and the usual high-order topological insulators.
Article
Computer Science, Artificial Intelligence
Shi-Xin Zhang, Chang-Yu Hsieh, Shengyu Zhang, Hong Yao
Summary: Variational quantum algorithms (VQAs) are speculated to provide quantum advantages for practical problems, with Quantum Architecture Search (QAS) being a method to design task-specific Parameterized Quantum Circuits (PQCs). A neural predictor guided QAS is shown to discover powerful quantum circuit solutions, outperforming random search baselines and capable of generalizing to address similar problems.
MACHINE LEARNING-SCIENCE AND TECHNOLOGY
(2021)