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Dissipative Chiral Channels, Ohmic Scaling and Half-integer Hall Conductivity from the Relativistic Quantum Hall Effect

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arXiv 2023年

作者： Zhou, Humian Chen, Chui-Zhen Sun, Qing-Feng Xie, X.C. International Center for Quantum Materials School of Physics Peking University Beijing100871 China School of Physical Science and Technology Soochow University Suzhou215006 China Institute for Advanced Study Soochow University Suzhou215006 China CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of Sciences Beijing100190 China Hefei National Laboratory Hefei230088 China Institute for Nanoelectronic Devices and Quantum Computing Fudan University Shanghai200433 China

The quantum Hall effect (QHE), which was observed in 2D electron gas under an external magnetic field, stands out as one of the most remarkable transport phenomena in condensed matter. However, a long standing puzzle remains regarding the observation of the relativistic quantum Hall effect (RQHE). This effect, predicted for a single 2D Dirac cone immersed in a magnetic field, is distinguished by the intriguing feature of half-integer Hall conductivity (HIHC). In this work, we demonstrate that the condensed-matter realization of the RQHE and the direct measurement of the HIHC are feasible by investigating the underlying quantum transport mechanism. We reveal that the manifestation of HIHC is tied to the presence of dissipative half-integer quantized chiral channels circulating along the interface of the RQHE system and a Dirac metal. Importantly, we find that the Ohmic scaling of the longitudinal conductance of the system plays a key role in directly measuring the HIHC in experiments. Furthermore, we propose a feasible experimental scheme based on the 3D topological insulators to directly measure the HIHC. Our findings not only uncover the distinct transport mechanism of the HIHC for the RQHE, but also paves the way to the measurement of the HIHC in future experiments. Copyright © 2023, The Authors. All rights reserved.

关键词： Quantum Hall effect

Chiral perturbation theory for heavy hadrons and chiral effective field theory for heavy hadronic molecules

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arXiv 2022年

作者： Meng, Lu Wang, Bo Wang, Guang-Juan Zhu, Shi-Lin Institute of theoretical physics II Department of physics and astronomy Ruhr-University Bochum Bochum44780 Germany School of Physical Science and Technology Hebei University Baoding071002 China Key Laboratory of High-precision Computation Application of Quantum Field Theory of Hebei Province Baoding071002 China Research Center for Computational Physics of Hebei Province Baoding071002 China Advanced Science Research Center Japan Atomic Energy Agency Ibaraki Tokai319-1195 Japan 1-1 Oho Ibaraki Tsukuba305-0801 Japan School of Physics Center of High Energy Physics Peking University Beijing100871 China

Chiral symmetry and its spontaneous breaking play an important role both in the light hadron and heavy hadron systems. The chiral perturbation theory (χPT) is the low energy effective field theory of the Quantum Chromodynamics. In this work, we shall review the investigations on the chiral corrections to the properties of the heavy mesons and baryons within the framework of χPT. We will also review the scatterings of the light pseudoscalar mesons and heavy hadrons, through which many new resonances such as the D∗s0(2317) could be understood. Moreover, many new hadron states were observed experimentally in the past decades. A large group of these states is near-threshold resonances, such as the charged charmoniumlike Zc and Zcs states, bottomoniumlike Zb states, hidden-charm pentaquark Pc and Pcs states and the doubly charmed Tcc state, etc. They are very good candidates of the loosely bound molecular states composed of a pair of charmed (bottom) hadrons, which are very similar to the loosely bound deuteron. The modern nuclear force was built upon the chiral effective field theory (χEFT), which is the extension of the χPT to the systems with two matter fields. The long-range and medium-long-range interactions between two nucleons arise from the single- and double-pion exchange respectively, which are well constrained by the chiral symmetry and its spontaneous breaking. The short-distance interactions can be described by the low energy constants. Such a framework works very well for the nucleon-nucleon scattering and nuclei. In this work, we will perform an extensive review of the progress on the heavy hadronic molecular states within the framework of χEFT. We shall emphasize that the same chiral dynamics not only govern the nuclei and forms the deuteron, but also dictates the shallow bound states or resonances composed of two heavy hadrons. Copyright © 2022, The Authors. All rights reserved.

关键词： Molecules

Quantum anomalous layer Hall effect in the topological magnet MnBi2Te4

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Physical Review B 2022年第24期106卷 245425-245425页

作者： Wen-Bo Dai Hailong Li Dong-Hui Xu Chui-Zhen Chen X. C. Xie International Center for Quantum Materials School of Physics Peking University Beijing 100871 China Beijing Academy of Quantum Information Sciences Beijing 100193 China Department of Physics and Chongqing Key Laboratory for Strongly Coupled Physics Chongqing University Chongqing 400044 China Center of Quantum Materials and Devices Chongqing University Chongqing 400044 China School of Physical Science and Technology Soochow University Suzhou 215006 China Institute for Advanced Study Soochow University Suzhou 215006 China Collaborative Innovation Center of Quantum Matter Beijing 100871 China CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of Sciences Beijing 100190 China

Recently, a type of Hall effect due to an unusual layer-locked Berry curvature called the layer Hall effect (LHE) has been reported in the even-layered two-dimensional antiferromagnetic (AFM) MnBi2Te4 [A. Gao et al., Nature (London) 595, 521 (2021)]. In this paper, we report that the quantization of LHE, which we call the quantum anomalous layer Hall effect (QALHE), can be realized in MnBi2Te4. The QALHE originates from kicking a layer-locked Berry curvature monopole out of the Fermi sea by a vertical electric field. Remarkably, we demonstrate that electric-field reversal can switch the sign of the quantized Hall conductance of QALHE in the even-layered AFM phase. The QALHE can also be realized in the ferromagnetic phase. These results provide a promising way toward the electric engineering of Berry curvature monopoles and quantized-layered transport in topological magnets.

关键词： Hall effect Quantum anomalous Hall effect Quantum transport Topological insulators Topological materials

Quantum gravity as a communication resource

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arXiv 2022年

作者： Howl, Richard Akil, Ali Kristjánsson, Hlér Zhao, Xiaobin Chiribella, Giulio Quantum Group Department of Computer Science University of Oxford Wolfson Building Parks Road OxfordOX1 3QD United Kingdom QICI Quantum Information and Computation Initiative Department of Computer Science The University of Hong Kong Pokfulam Road Hong Kong HKU-Oxford Joint Laboratory for Quantum Information and Computation Hong Kong Department of Physics Royal Holloway University of London Egham SurreyTW20 0EX United Kingdom Department of Physics Southern University of Science and Technology Shenzhen518055 China Department of Physics The Hong Kong University of Science and Technology Clear Water Bay Hong Kong Perimeter Institute for Theoretical Physics 31 Caroline Street North WaterlooONN2L 2Y5 Canada Institute for Quantum Computing University of Waterloo 200 University Avenue West WaterlooONN2L 3G1 Canada

Quantum information can provide a lens for characterizing the operational implications of spacetime physics. A well-known result in this area is that quantum entanglement is degraded in the vicinity of a black hole. This result treats the black hole and its spacetime as classical. But what if these were to be treated quantum-mechanically? Here, we show that quantum coherence in black hole, and thus spacetime, degrees of freedom can limit the degradation of entanglement, thereby improving the performance of nearby quantum communication protocols. This finding indicates that quantum features of spacetime could serve as resources for quantum information processing. Copyright © 2022, The Authors. All rights reserved.

关键词： Quantum entanglement

The Quantum Internet (Technical Version)

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arXiv 2025年

作者： Rohde, Peter P. Huang, Zixin Ouyang, Yingkai Huang, He-Liang Su, Zu-En Devitt, Simon Ramakrishnan, Rohit Mantri, Atul Tan, Si-Hui Liu, Nana Harrison, Scott Radhakrishnan, Chandrashekar Brennen, Gavin K. Baragiola, Ben Q. Dowling, Jonathan P. Byrnes, Tim Munro, William J. Centre for Quantum Software and Information Faculty of Engineering and Information Technology University of Technology Sydney SydneyNSW Australia Hearne Institute for Theoretical Physics Louisiana State University Baton Rouge United States School of Mathematical and Physical Sciences Macquarie University NSW2109 Australia School of Mathematical and Physical Sciences University of Sheffield SheffieldS3 7RH United Kingdom Henan Key Laboratory of Quantum Information and Cryptography Henan Zhengzhou450000 China Hefei National Laboratory for Physical Sciences at Microscale Department of Modern Physics University of Science & Technology of China Hefei China CAS Centre for Excellence and Synergetic Innovation Centre in Quantum Information & Quantum Physics University of Science & Technology of China Hefei China CAS-Alibaba Quantum Computing Laboratory Shanghai China InstituteQ Aalto University Espoo02150 Finland Indian Institute of Science Bangalore India Singapore University of Technology & Design Singapore Centre for Quantum Technologies National University of Singapore Singapore Horizon Quantum Ireland 24 Fitzwilliam Place Dublin 2 D02 T296 Ireland Institute of Natural Sciences Shanghai Jiao Tong University Shanghai200240 China School of Mathematical Sciences Shanghai Jiao Tong University Shanghai200240 China Ministry of Education Key Laboratory in Scientific and Engineering Computing Shanghai Jiao Tong University Shanghai200240 China Shanghai Artificial Intelligence Laboratory Shanghai China University of Michigan Shanghai Jiao Tong University Joint Institute Shanghai200240 China Leibniz Institute for Research & Information in Education Frankfurt am Main Germany Department of Computer Science and Engineering NYU Shanghai 567 West Yangsi Road Shanghai200124 China Centre of Excellence in Engineered Quantum Systems Macquarie University NSW Australia Centre for Quantum Computation and Communication Technology School of Science RMIT University VIC

The desire to share and unite remote digital assets motivated the development of the classical internet, the enabler of the entire 21st century economy and our modern way of life. As we enter the quantum era, it is to be expected there will be a similar demand for networking quantum assets, motivating a global quantum internet for bringing together the world's quantum resources, leveraging off their exponential trajectory in capability. We present models for quantum networking, how they might be applied in the future, and the implications they will have. Socially, economically, politically and geostrategically, the upcoming era of quantum supremacy will be as significant for the 21st century as the transistor was for the 20th. The inherently different scaling in the computational power of quantum computers fundamentally changes the dynamics of how they will operate in the future. Given their high expected initial cost, a client/server model for outsourcing computation will be essential for enabling the accessibility and proliferation of this technology, and ensuring its economic viability. We therefore anticipate the emergence of cloud quantum computing, a model for outsourcing quantum computations to the network. We argue that economic efficiency will mandate that all future quantum computers be united into a single global virtual quantum computer, offering exponentially more power to all network participants than if they were to keep their resources to themselves. This model for the allocation of computational resources is uniquely quantum, with no classical analogue, completely altering the economic landscape for the future of computation. Given the sensitivity of much of the data to which future quantum computers are going to foreseeably be applied, protocols for encrypted quantum computation will be essential - the outsourcing of computations that neither an eavesdropper nor even the server performing the computation can spy upon. This will enable new models fo

关键词： Outsourcing

Tight bound on neutron-star radius with quasiperiodic oscillations in short gamma-ray bursts

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arXiv 2024年

作者： Guedes, Victor Radice, David Chirenti, Cecilia Yagi, Kent Department of Physics University of Virginia CharlottesvilleVA22904 United States Institute for Gravitation & the Cosmos The Pennsylvania State University University ParkPA16802 United States Department of Physics The Pennsylvania State University University ParkPA16802 United States Department of Astronomy & Astrophysics The Pennsylvania State University University ParkPA16802 United States Department of Astronomy University of Maryland College ParkMD20742 United States Astroparticle Physics Laboratory NASA/GSFC GreenbeltMD20771 United States Center for Research and Exploration in Space Science and Technology NASA/GSFC GreenbeltMD20771 United States Center for Mathematics Computation and Cognition UFABC SP Santo André09210-170 Brazil

Quasiperiodic oscillations (QPOs) have been recently discovered in the short gamma-ray bursts (GRBs) 910711 and 931101B. Their frequencies are consistent with those of the quasiradial and quadrupolar oscillations of binary neutron star merger remnants, as obtained in numerical relativity simulations. These simulations reveal quasiuniversal relations between the remnant oscillation frequencies and the tidal coupling constant of the binaries. Under the assumption that the observed QPOs are due to these postmerger oscillations, we use the frequency-tide relations in a Bayesian framework to infer the source redshift, as well as the chirp mass and the binary tidal deformability of the binary neutron star progenitors for GRBs 910711 and 931101B. We further use this inference to estimate bounds on the mass-radius relation for neutron stars. By combining the estimates from the two GRBs, we find a 68% credible range R1.4 = 12.48+0−0.4140 km for the radius of a neutron star with mass M = 1.4 M☉, which is one of the tightest bounds to date. © 2024, CC BY.

关键词： Gamma rays

Giant Chern number of a Weyl nodal surface without upper limit

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Physical Review B 2022年第11期105卷 115118-115118页

作者： J.-Z. Ma S.-N. Zhang J. P. Song Q.-S. Wu S. A. Ekahana M. Naamneh M. Radovic V. N. Strocov S.-Y. Gao T. Qian H. Ding K. He K. Manna C. Felser N. C. Plumb O. V. Yazyev Y.-M. Xiong M. Shi Department of Physics City University of Hong Kong Kowloon Hong Kong China Photon Science Division Paul Scherrer Institute CH-5232 Villigen PSI Switzerland City University of Hong Kong Shenzhen Research Institute Shenzhen China Hong Kong Institute for Advanced Study City University of Hong Kong Kowloon Hong Kong China Institute of Physics École Polytechnique Fédérale de Lausanne CH-10 15 Lausanne Switzerland National Center for Computational Design and Discovery of Novel Materials MARVEL École Polytechnique Fédérale de Lausanne (EPFL) CH-1015 Lausanne Switzerland Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions High Magnetic Field Laboratory HFIPS Anhui Chinese Academy of Sciences Hefei 230031 China University of Science and Technology of China Hefei Anhui 230026 China Department of Physics Ben-Gurion University of the Negev Beer-Sheva 84105 Israel Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences Beijing 100190 China Songshan Lake Materials Laboratory Dongguan Guangdong China CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of Sciences Beijing 100049 China Department of Physics Tsinghua University Beijing 100084 China Max Planck Institute for Chemical Physics of Solids Dresden D-01187 Germany Department of Physics Indian Institute of Technology Delhi Hauz Khas New Delhi 110016 India Department of Physics School of Physics and Optoelectronics Engineering Anhui University Hefei 230601 China

Weyl nodes can be classified into zero-dimensional (0D) Weyl points, 1D Weyl nodal lines, and 2D Weyl nodal surfaces (WNS), which possess finite Chern numbers. Up to date, the largest Chern number of WPs identified in Weyl semimetals is 4, which is thought to be a maximal value for linearly crossing points in solids. On the other hand, whether the Chern numbers of nonzero-dimensional linear crossing Weyl nodal objects have one upper limit is still an open question. In this work, combining angle-resolved photoemission spectroscopy with density-functional theory calculations, we show that the chiral crystal AlPt hosts a cube-shaped charged WNS which is formed by the linear crossings of two singly degenerate bands. Different from conventional Weyl nodes, the cube-shaped nodal surface in AlPt is enforced by nonsymmorphic chiral symmetries and time-reversal symmetry rather than accidental band crossings, and it possesses a giant Chern number |C|=26. Moreover, our results and analysis prove that there is no upper limit for the Chern numbers of such kind of 2D Weyl nodal object.

关键词： Electronic structure First-principles calculations Symmetry protected topological states Topological materials Weyl semimetal Angle-resolved photoemission spectroscopy Density functional calculations

Identifying s-wave pairing symmetry in single-layer FeSe from topologically trivial edge states

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arXiv 2022年

作者： Wei, Zhongxu Qin, Shengshan Ding, Cui Hu, Jiangping Sun, Yujie Wang, Lili Xue, Qi-Kun Department of Physics Southern University of Science and Technology Shenzhen518055 China State Key Laboratory of Low-Dimensional Quantum Physics Department of Physics Tsinghua University Beijing10008 China Kavli Institute of Theoretical Sciences University of Chinese Academy of Sciences Beijing100049 China CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of Sciences Beijing100049 China Beijing Academy of Quantum Information Sciences Beijing100193 China Beijing National Research Center for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing100190 China

Determining the pairing symmetry of single-layer FeSe on SrTiO3 is the key to understanding the enhanced pairing mechanism;furthermore, it guides exploring new superconductors with high transition temperatures (Tc). Despite significant efforts, it remains controversial whether the symmetry is the sign-preserving s- or the sign-changed s±-wave. Here, we investigate the pairing symmetry of single-layer FeSe from a topological point of view. Using low-temperature scanning tunneling microscopy/spectroscopy, we have systematically characterized the superconducting states at isolated edges and corners of single-layer FeSe. The tunneling spectra collected at edges and corners exhibit full gap and substantial dip, respectively, demonstrating the absence of topologically non-trivial edge/corner modes. According to the theoretical calculation, these spectroscopic features are strong evidence for the sign-preserving s-wave pairing. © 2022, CC BY-NC-ND.

关键词： Iron compounds

Extragalactic Magnetar Giant Flares: Population Implications, Rates and Prospects for Gamma-Rays, Gravitational Waves and Neutrinos

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arXiv 2024年

作者： Beniamini, Paz Wadiasingh, Zorawar Trigg, Aaron Chirenti, Cecilia Burns, Eric Younes, George Negro, Michela Granot, Jonathan Department of Natural Sciences The Open University of Israel P.O Box 808 Ra'anana4353701 Israel The Open University of Israel P.O Box 808 Ra'anana4353701 Israel Department of Physics The George Washington University 725 21st Street NW WashingtonDC20052 United States Astrophysics Science Division NASA/GSFC GreenbeltMD20771 United States Department of Astronomy University of Maryland College ParkMD20742 United States Center for Research and Exploration in Space Science and Technology NASA/GSFC GreenbeltMD20771 United States Department of Physics & Astronomy Louisiana State University Baton RougeLA70803 United States Astroparticle Physics Laboratory NASA/GSFC GreenbeltMD20771 United States Center for Research and Exploration in Space Science and Technology NASA/GSFC GreenbeltMD20771 United States Center for Mathematics Computation and Cognition UFABC SP Santo Andre09210-170 Brazil CRESST Center for Space Sciences and Technology UMBC BaltimoreMD210250 United States

Magnetar Giant Flares (MGFs) are the most energetic non-catastrophic transients known to originate from stellar objects. The first discovered events were nearby. In recent years, several extragalactic events have been identified, implying an extremely high volumetric rate. We show that future instruments with a sensitivity 5×10−9 erg cm−2 at ∼ 1 MeV will be dominated by extragalactic MGFs over short gamma-ray bursts (sGRBs). Clear discrimination of MGFs requires intrinsic GRB localization capability to identify host galaxies. As MGFs involve a release of a sizable fraction of the neutron star’s magnetic free energy reservoir in a single event, they provide us with invaluable tools for better understanding magnetar birth properties and the evolution of their magnetic fields. A major obstacle is to identify a (currently) small sub-population of MGFs in a larger sample of more energetic and distant sGRBs. We develop the tools to analyze the properties of detected events and their occurrence rate relative to sGRBs. Even with the current (limited) number of events, we can constrain the initial internal magnetic field of a typical magnetar at formation to be B0 ≈ 4 × 1014 − 2 × 1015 G. Larger samples will constrain the distribution of birth fields. We also estimate the contribution of MGFs to the gravitational wave (GW) stochastic background. Depending on the acceleration time of baryon-loaded ejecta involved in MGFs, their GW emission may reach beyond 10 kHz and, if so, will likely dominate over other conventional astrophysical sources in that frequency range. © 2024, CC BY.

关键词： Neutrons