Review
Nanoscience & Nanotechnology
Youichi Yanase, Akito Daido, Kazuaki Takasan, Tsuneya Yoshida
Summary: This review discusses two-dimensional topological superconductivity based on non-chiral d-wave superconductors. It is demonstrated that noncentrosymmetric d-wave superconductors become topological superconductors under an infinitesimal Zeeman field without parameter fine-tuning. The use of Floquet engineering to introduce the Zeeman field in a controllable way is also proposed. Additionally, the potential of two-dimensional heterostructures of strongly correlated electron systems as a platform for high-temperature topological superconductivity and the interplay of topology and strong correlations in superconductors is explored.
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
(2022)
Article
Materials Science, Multidisciplinary
Gunnar F. Lange, Adrien Bouhon, Bartomeu Monserrat, Robert-Jan Slager
Summary: This article analyzes the band topology of acoustic phonons in 2D materials by considering the interplay between symmetries and additional constraints arising from the physical context. It shows that this interplay can lead to previously unaddressed nontrivial nodal charges in the phononic Brillouin zone. The analysis is applied to graphene and reveals the presence of these nontrivial nodal charges in its phonon spectrum. The findings are important for understanding how the phonon dispersion is affected when graphene is grown on a substrate.
Review
Multidisciplinary Sciences
Simon Yves, Xiang Ni, Andrea Alu
Summary: Topology is a branch of mathematics that studies the characteristics of objects that remain unchanged under continuous deformations. Recently, the powerful tools of topology have been used to study the electronic band structure of crystals, explaining topological phase transitions and the stability of certain band structures against perturbations. These findings have also led to the discovery of topological insulators, which have protected boundary states with unique transport properties. Furthermore, these discoveries have implications for sound control and manipulation technologies.
ANNALS OF THE NEW YORK ACADEMY OF SCIENCES
(2022)
Article
Optics
Xiang Ni, Seunghwi Kim, Andrea Alu
Summary: Recent advancements in implementing topological insulators in synthetic dimensions offer a way to explore higher-dimensional topological phases in compact systems. This study presents a two-dimensional topological insulator in a single-ring resonator using acousto-optic interactions and electro-optic modulation. The system reveals topological bulk and chiral edge bands in time-resolved absorption/transmission spectra, demonstrating reconfigurable and nonreciprocal frequency conversion controlled by probe frequency detuning.
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
Optics
Yixiao Wang, Anne-Sophie Walter, Gregor Jotzu, Konrad Viebahn
Summary: This study explores the possibilities of Floquet engineering in two dimensions using two-frequency driving. It reveals competing topological phases in a simple Bravais lattice when two resonant drives interfere. Additionally, it demonstrates the tuning of symmetry breaking in the hexagonal lattice through Floquet modulation. The potential applications include generating topological bands for ultracold atoms and realizing nonlinear Hall effects and Haldane's parity anomaly.
Article
Chemistry, Physical
Wei-Wang Yu, Ying Liu, Zeqing He, Lirong Wang, Xiaoming Zhang, Guodong Liu
Summary: The study reveals a novel combination of Weyl phonons in a two-dimensional system, consisting of two linear Weyl nodes and one quadratic Weyl node. The presence of the Weyl complex is facilitated by the coexistence of threefold symmetry - rotation symmetry, inversion symmetry, and time-reversal symmetry. The researchers construct tight-binding and effective k·p models to characterize the Weyl complex and investigate its unique phenomena, including edge states with three terminals.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Ning Mao, Runhan Li, Xiaorong Zou, Ying Dai, Baibiao Huang, Chengwang Niu
Summary: The interplay between ferroelectricity and band topology is studied in two-dimensional ferroelectrics. It is demonstrated that ferroelectricity and corner states are coupled together by crystallographic symmetry, allowing for electric control of higher-order topology. Experimental synthesis of two-dimensional ferroelectrics, such as In2Se3, BN, and SnS, is identified as realistic material candidates for ferroelectric higher-order topological insulators. This work provides insights into traditional ferroelectric materials and opens up avenues for manipulation of topology in next-generation electronic devices by bridging higher-order topology and ferroelectricity.
Article
Physics, Multidisciplinary
Lebing Chen, Jae-Ho Chung, Matthew B. Stone, Alexander Kolesnikov, Barry Winn, V. Ovidiu Garlea, Douglas L. Abernathy, Bin Gao, Mathias Augustin, Elton J. G. Santos, Pengcheng Dai
Summary: Researchers conducted a study using inelastic neutron scattering to investigate spin waves and Dirac gaps in CrI3, suggesting that Kitaev interactions and electron correlation effects are unable to explain these phenomena, while next-nearest-neighbor Dzyaloshinskii-Moriya interactions may be the microscopic origin of the Dirac gap.
Article
Astronomy & Astrophysics
Stephan Duerr, Johannes H. Weber
Summary: The two-dimensional Schwinger model is used to investigate how lattice fermion operators perceive the global topological charge of a given background gauge field. The study compares different types of fermions and finds that Karsten-Wilczek and Borici-Creutz fermions behave similarly to staggered and naive fermions in perceiving the global topological charge.
Article
Mathematics, Applied
Xingfei Xiang, Hexin Yang
Summary: This paper proves the existence of stable Meissner solutions for the Ginzburg-Landau equations of superconductivity in R2.
JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS
(2023)
Article
Physics, Multidisciplinary
Eli Chertkov, Benjamin Villalonga, Bryan K. Clark
Summary: The study shows the existence of many-body localization phenomena in quantum systems in higher dimensions, and an algorithm has been developed to search for approximate binary l bits. The algorithm successfully identified high-quality l bits in different models, and observed rapid changes in the distribution of l bits at specific disorder strengths, suggesting the presence of MBL transitions.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Mathematical
Jacob C. Bridgeman, Benjamin J. Brown, Samuel J. Elman
Summary: The topological entanglement entropy is used to measure long-range quantum correlations in topological phases, with closed form expressions obtained for (2+1)- and (3+1)-dimensional loop gas models. The study focuses on the formulation of results using generalized S-matrices, with a conjecture on their general property and proofs provided in specific cases, including categories up to rank 5.
COMMUNICATIONS IN MATHEMATICAL PHYSICS
(2022)
Article
Chemistry, Physical
Eduardo Costa Girao, Alastair Macmillan, Vincent Meunier
Summary: This article proposes a taxonomy for two-dimensional single-layer carbon allotropes, where each allotrope is assigned a unique symbol based on its geometry. The naming scheme is demonstrated for known structures and additional topology-allowed carbon systems. The symbol provides easy access to geometrical features and simplifies the classification of structures in the literature, which often have arbitrary names. This naming scheme will aid future studies on this class of systems. The energetic properties of the structures are also compared using consistent numerical parameters. The naming scheme can be extended to carbon systems with mixed hybridizations and other non-carbon 2D systems.
Article
Physics, Multidisciplinary
V. G. Yarzhemsky, E. A. Teplyakov
Summary: The research focuses on a complete group theoretical classification of chiral states in the D(6h) symmetry of topological superconductor UPt3, using the Anderson ansatz and induced representation method. It explores the topological structures of the superconducting order parameter and the connection with quantum mechanics and group theory.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2021)
Article
Physics, Particles & Fields
Jonah Kudler-Flam, Vladimir Narovlansky, Shinsei Ryu
Summary: The negativity spectrum, a measure of entanglement, is investigated in both pure and mixed states. A diagrammatic method and modification of the Ford-Fulkerson algorithm are used to find the negativity spectrum in random tensor networks and holographic states. New negativity spectra are discovered in these systems, as well as in phase transitions and wormholes.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
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
Shinsei Ryu, Junggi Yoon
Summary: We study the two-dimensional free symplectic fermion theory with antiperiodic boundary condition and address the issue of negative norm states. By introducing a new inner product, we demonstrate that this problem can be resolved. Moreover, we establish the connection between the path integral formalism and the operator formalism in deriving this new inner product. Additionally, we investigate α vacua in which the Hamiltonian appears non-Hermitian, yet the energy spectrum is found to be real. We also compare the correlation function between the α vacua and the de Sitter space.
PHYSICAL REVIEW LETTERS
(2023)
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
Anish Kulkarni, Tokiro Numasawa, Shinsei Ryu
Summary: In this study, the Lindbladian dynamics of the Sachdev-Ye-Kitaev (SYK) model coupled to Markovian reservoirs with different types of jump operators was investigated. Analytical results for the stationary Green's functions and decay rates of the SYK Lindbladians were obtained in the large N and large N/M limits. The distribution of eigenvalues of SYK Lindbladians for finite N was also analyzed.
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
Astronomy & Astrophysics
Ki-Seok Kim, Shinsei Ryu, Kanghoon Lee
Summary: In holographic duality, a theory framework that describes the renormalization group flow of a quantum field theory by introducing additional dimensions, we develop a new holographic description that encodes the information of the renormalization group flow and the quantum field theory into an effective field theory. We demonstrate the self-consistency of this dual construction under the assumption of bulk locality.
Article
Materials Science, Multidisciplinary
Yuhan Liu, Ramanjit Sohal, Jonah Kudler-Flam, Shinsei Ryu
Summary: We study multipartitions of the gapped ground states of (2+1)-dimensional topological liquids and compute various correlation measures. By introducing vertex states in (1+1)-dimensional conformal field theory, we can explicitly construct the reduced density matrix. The results provide important insights and applications for understanding and utilizing topological liquids.
