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Robust orbital diamagnetism of correlated Dirac fermions in chiral Ising universality class

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arXiv 2021年

作者： Tada, Yasuhiro Quantum Matter Program Graduate School of Advanced Science and Engineering Hiroshima University Hiroshima Higashihiroshima739-8530 Japan Institute for Solid State Physics University of Tokyo Kashiwa277-8581 Japan

We study orbital diamagnetism at zero temperature in (2 + 1)-dimensional Dirac fermions with a short-range interaction which exhibits a quantum phase transition to a charge density wave (CDW) phase. We introduce orbital magnetic fields into spinless Dirac fermions on the π-flux square lattice, and analyze them by using infinite density matrix renormalization group. It is found that the diamagnetism remains intact in the Dirac semimetal regime as a result of a non-trivial competition between the enhanced Fermi velocity and magnetic-field-induced mass gap, while it is monotonically suppressed in the CDW regime. Around the quantum critical point (QCP) of the CDW phase transition, we find a scaling behavior of the diamagnetism characteristic of the chiral Ising universality class. This defines a universal behavior of orbital diamagnetism in correlated Dirac fermions around a QCP, and therefore the robust diamagnetism in the semimetal regime is a universal property of Dirac systems whose criticality belongs to the chiral Ising universality class. The scaling behavior may also be regarded as a quantum, magnetic analogue of the critical Casimir effect which has been widely studied for classical phase transitions. Copyright © 2021, The Authors. All rights reserved.

关键词： Charge density

Generating function for projected entangled-pair states

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arXiv 2023年

作者： Tu, Wei-Lin Vanderstraeten, Laurens Schuch, Norbert Lee, Hyun-Yong Kawashima, Naoki Chen, Ji-Yao Faculty of Science and Technology Keio University 3-14-1 Hiyoshi Kohoku-ku Yokohama223-8522 Japan Center for Nonlinear Phenomena and Complex Systems Université Libre de Bruxelles Belgium University of Vienna Faculty of Physics Boltzmanngasse 5 Wien1090 Austria University of Vienna Faculty of Mathematics Oskar-Morgenstern-Platz 1 Wien1090 Austria Division of Display and Semiconductor Physics Korea University Sejong30019 Korea Republic of Department of Applied Physics Graduate School Korea University Sejong30019 Korea Republic of Interdisciplinary Program in E·ICT-Culture-Sports Convergence Korea University Sejong30019 Korea Republic of Institute for Solid State Physics The University of Tokyo Chiba Kashiwa277-8581 Japan Trans-scale Quantum Science Institute The University of Tokyo Bunkyo Tokyo113-0033 Japan Center for Neutron Science and Technology Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices School of Physics Sun Yat-sen University Guangzhou510275 China

Diagrammatic summation is a common bottleneck in modern applications of projected entangled-pair states, especially in computing low-energy excitations of a two-dimensional quantum many-body system. To solve this problem, here we extend the generating function approach for tensor network diagrammatic summation, a scheme previously proposed in the context of matrix product states. Taking the form of a one-particle excitation, we show that the excited state can be computed efficiently in the generating function formalism, which can further be used in evaluating the dynamical structure factor of the system. Our benchmark results for the spin-1/2 transverse-field Ising model and Heisenberg model on the square lattice provide a desirable accuracy, showing good agreement with known results. We then study the spin-1/2 J1-J2 model on the same lattice and investigate the dynamical properties of the putative gapless spin liquid phase. We conclude with a discussion on generalizations to multi-particle excitations. © 2023, CC BY.

关键词： Excited states

Structural, optical, and thermal properties of BN thin films grown on diamond via pulsed laser deposition

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Physical Review Materials 2023年第9期7卷 094602-094602页

作者： Abhijit Biswas Gustavo A. Alvarez Tao Li Joyce Christiansen-Salameh Eugene Jeong Anand B. Puthirath Sathvik Ajay Iyengar Chenxi Li Tia Gray Xiang Zhang Tymofii S. Pieshkov Harikishan Kannan Jacob Elkins Robert Vajtai A. Glen Birdwell Mahesh R. Neupane Elias J. Garratt Bradford B. Pate Tony G. Ivanov Yuji Zhao Zhiting Tian Pulickel M. Ajayan Department of Materials Science and Nanoengineering Rice University Houston Texas 77005 USA Sibley School of Mechanical and Aerospace Engineering Cornell University Ithaca New York 14853 USA Department of Electrical and Computer Engineering Rice University Houston Texas 77005 USA Applied Physics Graduate Program Smalley-Curl Institute Rice University Houston Texas 77005 USA DEVCOM Army Research Laboratory RF Devices and Circuits Adelphi Maryland 20783 USA Naval Research Laboratory Chemistry Division Washington District of Columbia 20375 USA

Heterostructures based on ultrawide-bandgap (UWBG) semiconductors (bandgap>4.0eV), such as BN and diamond, hold significant importance for the development of high-power electronics in the next generation. However, achieving in situ heteroepitaxy of BN/diamond or vice versa remains exceptionally challenging due to the complex growth kinetics involved. In this work, we grew BN thin film on (100) single-crystal diamonds using pulsed laser deposition and investigated its structural, magnetic, optical, and thermal properties. The structural analyses confirmed the growth of BN films, which exhibited diamagnetic behavior at room temperature. Notably, the film demonstrated anisotropic refractive index characteristics within the visible-to-near-infrared wavelength range. The room-temperature cross-plane thermal conductivity of BN is 1.53 ± 0.77 W/mK, while the thermal conductance of the BN/diamond interface is 20±2MW/m2K. These findings have significant implications for a range of device applications based on UWBG BN/diamond heterostructures.

关键词： Growth Thermal conductivity Boron nitride Thin films Wide band gap systems Film deposition Laser ablation Thermoreflectance

Lieb-Schultz-Mattis theorem in higher dimensions from approximate magnetic translation symmetry

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arXiv 2021年

We prove the Lieb-Schultz-Mattis (LSM) theorem on the energy spectrum of a general two or three-dimensional quantum many-body system with the U(1) particle number conservation and translation symmetry. Especially, it is demonstrated that the theorem holds in a system with long-range interactions. To this end, we introduce approximate magnetic translation symmetry under the total magnetic flux Φ = 2π instead of the exact translation symmetry, and explicitly construct low energy variational states. The energy spectrum at Φ = 2π is shown to agree with that at Φ = 0 in the thermodynamic limit, which concludes the LSM theorem. Copyright © 2021, The Authors. All rights reserved.

关键词： Spectroscopy

Topological Edge State Nucleation in Frequency Space and its Realization with Floquet Electrical Circuits

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arXiv 2024年

作者： Stegmaier, Alexander Fritzsche, Alexander Sorbello, Riccardo Greiter, Martin Brand, Hauke Barko, Christine Hofer, Maximilian Schwingenschlögl, Udo Moessner, Roderich Lee, Ching Hua Szameit, Alexander Alù, Andrea Kießling, Tobias Thomale, Ronny Institute for Theoretical Physics and Astrophysics University of Würzburg Am Hubland WürzburgD-97074 Germany Physikalisches Institut Röntgen Research Center for Complex Material Systems Universität Würzburg WürzburgD-97074 Germany Thuwal23955 Saudi Arabia Max Planck Institute for the Physics of Complex Systems Nöthnitzer Straße 38 Dresden01187 Germany Würzburg-Dresden Cluster of Excellence ct.qmat WürzburgD-97074 Germany Department of Physics National University of Singapore Singapore117542 Singapore Institute of Physics University of Rostock Rostock Germany Photonics Initiative Advanced Science Research Center City University of New York New YorkNY10031 United States Physics Program Graduate Center City University of New York New YorkNY10016 United States

We build Floquet-driven capactive circuit networks to realize topological states of matter in the frequency domain. We find the Floquet circuit network equations of motion to reveal a potential barrier which effectively acts as a boundary in frequency space. By implementing a Su-Shrieffer-Heeger Floquet lattice model and measuring the associated circuit Laplacian and characteristic resonances, we demonstrate how topological edge modes can nucleate at such a frequency boundary. © 2024, CC BY.

关键词： Equations of motion

Polar self-organization of ferroelectric nematic liquid crystal molecules on atomically flat Au(111) surface

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arXiv 2024年

作者： Marchenko, Alexandr A. Kapitanchuk, Oleksiy L. Lopatina, Yaroslava Yu. Nazarenko, Kostiantyn G. Senenko, Anton I. Katsonis, Nathalie Nazarenko, Vassili G. Lavrentovich, Oleg D. Institute of Physics The National Academy of Sciences of Ukraine 46 Nauki ave. Kyiv03028 Ukraine Stratingh Institute for Chemistry University of Groningen Nijenborgh 4 Groningen9747AG Netherlands Bogolyubov Institute for Theoretical Physics The National Academy of Sciences of Ukraine 14-B Metrologichna str. Kyiv03143 Ukraine Institute of Organic Chemistry The National Academy of Sciences of Ukraine Kyiv Ukraine Enamine Ltd Kyiv Ukraine Institute of Physical Chemistry PAS Kasprzaka 44/52 Warsaw01-224 Poland Advanced Materials and Liquid Crystal Institute Department of Physics Materials Science Graduate Program Kent State University KentOH44242 United States

Understanding nanoscale mechanisms responsible for the recently discovered ferroelectric nematics can be helped by direct visualization of self-assembly of strongly polar molecules. Here we report on scanning tunneling microscopy (STM) studies of monomolecular layers of a ferroelectric nematic liquid crystal on a reconstructed Au(111) surface. The monolayers are obtained by deposition from a solution at ambient conditions. The adsorbed ferroelectric nematic molecules self-assemble into regular rows with tilted orientation, resembling a layered structure of a smectic C. Remarkably, each molecular dipole in this architecture is oriented along the same direction giving rise to polar ferroelectric ordering. Copyright © 2024, The Authors. All rights reserved.

关键词： Nematic liquid crystals

GNOME and LBM model evaluation on ocean oil spill far-field impacts to highly sensitive areas

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arXiv 2021年

作者： Zhang, Zhanyang Schäfer, Tobias Kress, Michael E. Doctoral Program in Computer Science The Graduate Center City University of New York 365 5th Avenue New YorkNY10016 United States Doctoral Program in Physics The Graduate Center City University of New York 365 5th Avenue New YorkNY10016 United States

In case of an ocean oil spill, there are certain areas, e.g. shrimp farms, which are highly sensitive to small amounts of oil pollution while they are geographically far from the spill. We investigate the Lattice Boltzmann Method (LBM) and GNOME, a tool developed and used by NOAA, in terms of far-field impacts to sensitive areas. We present our simulation results of both models in limited scale (a sub area of Gulf of Mexico) under the same oil spill condition using real ocean current data from the Unified Wave Interface-Coupled Model (UWIN-CM). Our study shows that the kinetic theory based LBM model outperforms the stochastic particle based GNOME model in accuracy and computation time due to their fundamental difference in representation of oil pollution advection and diffusion mechanisms. We propose LBM as a viable alternative to the Lagrangian particle calculation component of GNOME in modeling the far-field impacts to highly sensitive *** Codes 37N10, 65M75, 76R50 Copyright © 2021, The Authors. All rights reserved.

关键词： Kinetic theory

Hyperspectral spectro-imager survey for state of art concept identification

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Hyperspectral spectro-imager survey for state of art concept...

2020 International Conference on Space Optics, ICSO 2020

作者： Wanajaroen, Weerapot Lépine, Thierry Buisset, Christophe Castelnau, Matthieu Costes, Vincent Wannawichian, Suwicha Poshyachinda, Saran Soonthornthuma, Boonrucksar T. Donkaew A. Maerim 260 Moo 4 Chiangmai50180 Thailand Doctor of Philosophy Degree Program in Astronomy Department of Physics and Materials Science Faculty of Science Chiang Mai University Chiang Mai50200 Thailand Institut d'Optique Graduate School 18 rue Benoît Lauras Saint-Etienne42000 France Laboratoire Hubert Curien Université de Lyon CNRS 18 rue Benoît Lauras Saint-EtienneF-42000 France CNES 18 Avenue Edouard Belin Toulouse Cedex 931401 France Department of Physics and Materials Science Faculty of Science Chiang Mai University Chiang Mai50200 Thailand

Over the past twenty years, a very high number of different space hyperspectral spectrometers have been designed, developed and launched. Recently, several new compact designs based on freeform optics have been proposed in the literature. We thus considered that it was interesting to make a survey of the already existing hyperspectral imagers and innovative freeform designs to identify the most promising solutions to increase the compactness and the performance. Some surveys on hyperspectral imagers have already been done in the past. For example, the survey by Herring et al, in 1993 which proposed some hyperspectral spectrometer concepts. However, these studies are now outdated and cannot be used to identify state of art concepts. The review proposed by Kumar et al., in 2015 presented the advantages to browse the different hyperspectral imager concepts but provided only superficial technical details that cannot be used to identify the specific designs that improve both the compactness and the image and spectral qualities. We thus decided to make a bibliographic survey to analyze the most recent designs of different space hyperspectral imagers with the objective to select the concepts that will provide the best compromise between the volume and the performance. We have categorized the different systems into four groups: prism based, Offner, Three Mirror Anastigmat (TMA) and Dyson spectrometers. We analyzed these different concepts and we identified and the advantages and the drawbacks. We concluded that the most interesting state-of-art designs are the Freeform Offner, double-pass TMA and Dyson spectrometers. These designs present the most interesting performance and combine with a compact volume. We thus established a preliminary trade-off that summarizes the advantages and the drawback of these concepts. This trade-off analysis could be used as a starting point for any future study aiming at designing compact hyperspectral imager. Finally, we present the progress

关键词： Surveys

Entanglement and Purification Transitions in Non-Hermitian Quantum Mechanics

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Physical Review Letters 2021年第17期126卷 170503-170503页

作者： Sarang Gopalakrishnan Michael J. Gullans Department of Physics The Pennsylvania State University University Park Pennsylvania 16802 USA Department of Physics and Astronomy CUNY College of Staten Island Staten Island New York 10314 and Physics Program and Initiative for the Theoretical Sciences The Graduate Center CUNY New York New York 10016 USA Joint Center for Quantum Information and Computer Science NIST/University of Maryland College Park Maryland 20742 USA

A quantum system subject to continuous measurement and postselection evolves according to a non-Hermitian Hamiltonian. We show that, as one increases the strength of postselection, this non-Hermitian Hamiltonian can undergo a spectral phase transition. On one side of this phase transition (for weak postselection), an initially mixed density matrix remains mixed at all times, and an initially unentangled state develops volume-law entanglement; on the other side, an arbitrary initial state approaches a unique pure state with low entanglement. We identify this transition with an exceptional point in the spectrum of the non-Hermitian Hamiltonian, at which PT symmetry is spontaneously broken. We characterize the transition as well as the nontrivial steady state that emerges at late times in the mixed phase using exact diagonalization and an approximate, analytically tractable mean-field theory; these methods yield consistent conclusions.

关键词： Dynamical phase transitions Entanglement production Open quantum systems PT-symmetric quantum mechanics Quantum measurements Quantum phase transitions