检索结果-内蒙古大学图书馆

Deformed Fredkin model for the ν=5/2 Moore-Read state on thin cylinders

学校读者我要写书评

暂无评论

Physical Review Research 2024年第1期6卷 013105-013105页

作者： Cristian Voinea Songyang Pu Ammar Kirmani Pouyan Ghaemi Armin Rahmani Zlatko Papić School of Physics and Astronomy University of Leeds Leeds LS2 9JT United Kingdom Theoretical Division T-4 Los Alamos National Laboratory Los Alamos New Mexico 87545 USA Physics Department City College of the City University of New York New York 10031 USA Physics Program Graduate Center of City University of New York New York 10031 USA Department of Physics and Astronomy and Advanced Materials Science and Engineering Center Western Washington University Bellingham Washington 98225 USA

We propose a frustration-free model for the Moore-Read quantum Hall state on sufficiently thin cylinders with circumferences ≲7 magnetic lengths. While the Moore-Read Hamiltonian involves complicated long-range interactions between triplets of electrons in a Landau level, our effective model is a simpler one-dimensional chain of qubits with deformed Fredkin gates. We show that the ground state of the Fredkin model has high overlap with the Moore-Read wave function and accurately reproduces the latter's entanglement properties. Moreover, we demonstrate that the model captures the dynamical response of the Moore-Read state to a geometric quench, induced by suddenly changing the anisotropy of the system. We elucidate the underlying mechanism of the quench dynamics and show that it coincides with the linearized bimetric field theory. The minimal model introduced here can be directly implemented as a first step towards quantum simulation of the Moore-Read state, as we demonstrate by deriving an efficient circuit approximation to the ground state and implementing it on an IBM quantum processor.

关键词： Fractional quantum Hall effect Quantum computation Quantum many-body systems Strongly correlated systems Exact diagonalization Matrix product states

Characterizing the mechanical response of metallic glasses to uniaxial tension using a spring network model

学校读者我要写书评

暂无评论

Physical Review materials 2023年第7期7卷 073605-073605页

作者： Aya Nawano Weiwei Jin Jan Schroers Mark D. Shattuck Corey S. O'Hern Department of Mechanical Engineering and Materials Science Yale University New Haven Connecticut 06520 USA Benjamin Levich Institute and Physics Department The City College of New York New York New York 10031 USA Department of Physics Yale University New Haven Connecticut 06520 USA Department of Applied Physics Yale University New Haven Connecticut 06520 USA Graduate Program in Computational Biology and Bioinformatics Yale University New Haven Connecticut 06520 USA

A coarse-grained spring network model is proposed for the prediction of the mechanical response of metallic glasses as a function of the microstructure prior to loading. This model describes the mechanical response of metallic glasses using a network of parallel springs that can break and reform, mimicking atomic rearrangements during deformation. We compare predictions of the spring network model for stress versus strain to results from numerical simulations of athermal quasistatic, uniaxial tensile deformation of Cu50Zr50 metallic glasses using Lennard-Jones (LJ) and embedded atom method (EAM) atomic interactions. We show that both the LJ and EAM models possess qualitatively similar stress σ versus strain γ curves. By specifying five parameters [ultimate strength, strain at ultimate strength, slopes of σ(γ) at γ=0 and at large strain, and strain at fracture where σ=0], we demonstrate that the spring network model can accurately describe the form of the stress-strain curves during uniaxial tension for the computational studies of Cu50Zr50, as well as recent experimental studies of several Zr-based metallic glasses.

关键词： Alloys Amorphous materials Glasses Packing & jamming problems Molecular dynamics

Perovskite detectors for x-ray imaging and gamma spectroscopy: Overview and current state-of-The-Art 23

学校读者我要写书评

暂无评论

Perovskite detectors for x-ray imaging and gamma spectroscop...

Hard X-Ray, Gamma-Ray, and Neutron Detector physics XXIII 2021

作者： Cao, Lei R. Pan, Lei Kandlakunta, Praneeth Nie, Wanyi Nuclear Engineering Program Department of Mechanical and Aerospace Engineering The Ohio State University ColumbusOH43210 United States Center for Integrated Nanotechnology Materials Physics and Application Division Los Alamos National Laboratory Los AlamosNM87545 United States

ISBN: (数字)9781510645158

ISBN: (纸本)9781510645141

Perovskites are a family of semiconductor materials with molecular formula ABX3 [where A+ = Cesium (Cs), methylammonium (MA or CH3NH3) or formamidinium (FA or CH(NH2)2), B-site is metal, and X-= chlorine (Cl), bromine (Br) or iodine (I)] that have recently seen a surged interest for X-ray and gamma-ray detection. The all inorganic version, CsPbBr3, grown by high temperature melt method has been demonstrated with an impressive gamma-ray energy resolution of 1.4%@662 keV, while the solution grown CsPbBr3 showed the best achievable resolution of 5.5% at the same energy from a 137Cs source. This paper gives an overview of the development of perovskite in both X-ray detection and gamma spectroscopy, including the most recent advancement with perovskite single crystal grown by low temperature inverse temperature method for solid-state X-ray detector. The crystal shows a decent long carrier diffusion length that is ideal for charge collection, while their mobilities are still not on par with CdZnTe. We also reported our most recent development on clarifying the concepts around X-ray detection limits. The X-ray sensitivity and the lowest detectable dose rate (i.e., X-ray detection limits) of several MAPbI3 detectors made of single crystal were experimentally measured. The best achieved X-ray sensitivity is ∼2.5E4 μC/Gyair/cm2 under 15.4 V/mm, which is comparable to the current state-of-The-Art MAPbI3based X-ray detectors (∼ 2.3E4 μC/Gyair/cm2 under 4.2 V/mm for GAMAPbI3 (GA=guanidinium) single crystal detector). The best achieved lowest detectable X-ray dose rate for the same MAPbI3 detector is ∼61 nGyair/s under 15.4 V/mm, and decreased to ∼24 nGyair/s under 3.8 V/mm. The good performance of the MAPbI3 detectors further proves their great potential as the next generation low-cost X-ray detector. © COPYRIGHT SPIE.

关键词： X ray detectors

Spectroscopic investigation and local structure of Eu3+ ions in lead phosphate glasses for optical device applications

学校读者我要写书评

暂无评论

Optik 2024年 300卷

作者： Basavapoornima, Ch. Masthanaiah, E. Vijaya, N. Depuru, Shobha Rani Kaewkhao, J. Pecharapa, Wisanu Jayasankar, C.K. Department of Physics Sri Venkateswara University Tirupati517 502 India Institute of Aeronautical Engineering Hyderabad500 043 India Physics Program Faculty of Science and Technology Nakhon Pathom Rajabhat University Pathom Nakhon73000 Thailand Nakhon Pathom Rajabhat University Pathom Nakhon73000 Thailand College of Materials Innovation and Technology King Mongkut's Institute of Technology Ladkrabang Bangkok Ladkrabang10520 Thailand

Phosphate-based glasses are promising materials which are being employed for broad range of applications whereas Eu3+ is an efficient activator due to its predominant 5D0 →7F2 emission (red region). In this direction, an attempt has been made to investigate the effect of Eu3+ ions doped lead phosphate glasses (PPbKANEu: P2O5+PbO+K2O+Al2O3+Na2O+Eu2O3) to explore possible photonic device applications. Optical absorption, excitation, photoluminescence and decay rates are used to characterize the PPbKANEu glasses. The photoluminescence spectrum of Eu3+:PPbKAN glasses exhibit emission channels from the first excited (5D0) to the ground (7FJ (J =0–4)) multiplets. To determine the local site symmetry of surrounding Eu3+ ions, the relative fluorescence intensity ratio of 5D0→7F1 versus 5D0→7F2 emission channels has been analyzed. The emission spectrum of PPbKANEu glasses exhibits a comprehensive lifting of degeneracy of 5D0→7F2 and 5D0→7F1 emission channels. By considering C2v symmetry for Eu3+ ions, the second (B02= −406 and B22=−158) and fourth (B04=980, B24=297 and B44=926 cm–1) rank crystal–field (CF) characteristics were estimated along with CF strength factor (S= 402 cm–1). The lifetime of 5D0 state is estimated to be 2.09, 2.23, 2.21 and 2.21 ms for 0.1, 0.5, 1.0 and 2.0 mol% of Eu3+ ions, respectively. The analysis of the decay times reveals that the lifetime of 5D0 state is less affected by the concentration of the Eu3+ ion. The results are compared and discussed with reported values and confirm the potentiality of the PPbKANEu glasses for optical device applications in visible regions. © 2024 Elsevier GmbH

关键词： Ions

Emulating complex synapses using interlinked proton conductors

学校读者我要写书评

暂无评论

Physical Review Applied 2025年第1期23卷 014027-014027页

作者： Lifu Zhang Ji-An Li Yang Hu Jie Jiang Rongjie Lai Marcus K. Benna Jian Shi Department of Materials Science and Engineering Rensselaer Polytechnic Institute Troy New York 12180 USA Neurosciences Graduate Program University of California San Diego La Jolla California 92093 USA Department of Mathematics Purdue University West Lafayette Indiana 47907 USA Department of Neurobiology School of Biological Sciences University of California at San Diego La Jolla California 92093 USA Department of Physics Applied Physics and Astronomy Rensselaer Polytechnic Institute Troy New York 12180 USA

In terms of energy efficiency and computational speed, neuromorphic electronics based on nonvolatile memory devices are expected to be one of most promising hardware candidates for future artificial intelligence (AI). However, catastrophic forgetting, networks rapidly overwriting previously learned weights when learning new tasks, remains a pivotal obstacle in either digital or analog AI chips for unleashing the true power of brainlike computing. To address catastrophic forgetting in the context of online memory storage, a complex synapse model (the Benna-Fusi model) was proposed recently [M. K. Benna and S. Fusi, Nat. Neurosci. 19, 1697 (2016)], the synaptic weight and internal variables of which evolve following diffusion dynamics. In this work, by designing a proton transistor with a series of charge-diffusion-controlled storage components, we have experimentally realized the Benna-Fusi artificial complex synapse. Memory consolidation from coupled storage components is revealed by both numerical simulations and experimental observations. Different memory timescales for the complex synapse are engineered by the diffusion length of charge carriers and the capacity and number of coupled storage components. The advantages of the demonstrated complex synapse for both memory capacity and memory consolidation are revealed by neural network simulations of face-familiarity detection. Our experimental realization of the complex synapse suggests a promising approach to enhance memory capacity and to enable continual learning.

关键词： Nonvolatile storage

Impact of Quantum Well Thickness on Efficiency Loss in InGaN/GaN LEDs: Challenges for Thin-Well Designs

学校读者我要写书评

暂无评论

arXiv 2025年

作者： Li, Xuefeng Pant, Nick Rahman, Sheikh Ifatur Armitage, Rob Rajan, Siddharth Kioupakis, Emmanouil Feezell, Daniel University of New Mexico AlbuquerqueNM87106 United States Department of Materials Science & Engineering University of Michigan Ann ArborMI48109 United States Applied Physics Program University of Michigan Ann ArborMI48109 United States Department of Electrical and Computer Engineering The Ohio State University ColumbusOH43210 United States Lumileds LLC San JoseCA95131 United States Department of Materials Science and Engineering The Ohio State University ColumbusOH43210 United States

We investigate the impact of quantum well (QW) thickness on efficiency loss in c-plane InGaN/GaN LEDs using a small-signal electroluminescence (SSEL) technique. Multiple mechanisms related to efficiency loss are independently examined, including injection efficiency, carrier density vs. current density relationship, phase space filling (PSF), quantum confined stark effect (QCSE), and Coulomb enhancement. An optimal QW thickness of around 2.7 nm in these InGaN/GaN LEDs was determined for quantum wells having constant In composition. Despite better control of deep-level defects and lower carrier density at a given current density, LEDs with thin QWs still suffer from an imbalance of enhancement effects on the radiative and intrinsic Auger-Meitner recombination coefficients. The imbalance of enhancement effects results in a decline in internal quantum efficiency (IQE) and radiative efficiency with decreasing QW thickness at low current density in LEDs with QW thicknesses below 2.7 nm. We also investigate how LED modulation bandwidth varies with quantum well thickness, identifying the key trends and their implications for device performance. Copyright © 2025, The Authors. All rights reserved.

关键词： Semiconductor quantum wells

Emergent dimer-model topological order and quasi-particle excitations in liquid crystals: combinatorial vortex lattices

学校读者我要写书评

暂无评论

arXiv 2025年

作者： Meng, Cuiling Wu, Jin-Sheng Kos, Žiga Dunkel, Jörn Nisoli, Cristiano Smalyukh, Ivan I. Department of Physics and Chemical Physics Program University of Colorado BoulderCO80309 United States Hiroshima University Hiroshima Higashihiroshima Japan Department of Mathematics Massachusetts Institute of Technology CambridgeMA02139 United States Faculty of Mathematics and Physics University of Ljubljana Ljubljana Slovenia Department of Condensed Matter Physics Jožef Stefan Institute Ljubljana Slovenia Theoretical Division Physics of Condensed Matter and Complex Systems Center For Nonlinear Studies Los Alamos National Laboratory Los AlamosNM87545 United States Department of Electrical Computer and Energy Engineering Materials Science and Engineering Program University of Colorado BoulderCO80309 United States Renewable and Sustainable Energy Institute National Renewable Energy Laboratory University of Colorado BoulderCO80309 United States

Liquid crystals have proven to provide a versatile experimental and theoretical platform for studying topological objects such as vortices, skyrmions, and hopfions. In parallel, in hard condensed matter physics, the concept of topological phases and topological order has been introduced in the context of spin liquids to investigate emergent phenomena like quantum Hall effects and high-temperature superconductivity. Here, we bridge these two seemingly disparate perspectives on topology in physics. Combining experiments and simulations, we show how topological defects in liquid crystals can be used as versatile building blocks to create complex, highly degenerate topological phases, which we refer to as ‘Combinatorial Vortex Lattices’ (CVLs). CVLs exhibit extensive residual entropy and support locally stable quasi-particle excitations in the form of charge-conserving topological monopoles, which can act as mobile information carriers and be linked via Dirac strings. CLVs can be rewritten and reconfigured on demand, endowed with various symmetries, and modified through laser-induced topological surgery — an essential capability for information storage and retrieval. We demonstrate experimentally the realization, stability, and precise optical manipulation of CVLs, thus opening new avenues for understanding and technologically exploiting higher-hierarchy topology in liquid crystals and other ordered media. Copyright © 2025, The Authors. All rights reserved.

关键词： Laser surgery

Correlation versus dissipation in a non-Hermitian Anderson impurity model

学校读者我要写书评

暂无评论

arXiv 2024年

作者： Yamamoto, Kazuki Nakagawa, Masaya Kawakami, Norio Department of Physics Tokyo Institute of Technology Meguro Tokyo152-8551 Japan Department of Physics University of Tokyo Hongo Tokyo113-0033 Japan Fundamental Quantum Science Program TRIP Headquarters RIKEN Wako351-0198 Japan Department of Physics Ritsumeikan University Shiga Kusatsu525-8577 Japan Department of Materials Engineering Science Osaka University Toyonaka Osaka560-8531 Japan

We analyze the competition between strong correlations and dissipation in quantum impurity systems from the Kondo regime to the valence fluctuation regime by developing a slave-boson theory for a non-Hermitian Anderson impurity model with one-body loss. Notably, in the non-Hermitian Kondo regime, strong correlations qualitatively change the nature of dissipation through renormalization effects, where the effective one-body loss is suppressed and emergent many-body dissipation characterized by the complex-valued hybridization is generated. We unveil the mechanism of a dissipative quantum phase transition of the Kondo state on the basis of this renormalization effect, which counterintuitively enhances the lifetime of the impurity against loss. We also find a crossover from the non-Hermitian Kondo regime to the valence fluctuation regime dominated by one-body dissipation. Our results can be tested in a wide variety of setups such as quantum dots coupled to electronic leads and quantum point contacts in ultracold Fermi gases. Copyright © 2024, The Authors. All rights reserved.

关键词： Bosons

Ultrafast evanescent heat transfer across solid interfaces via hyperbolic phonon-polaritons in hexagonal boron nitride

学校读者我要写书评

暂无评论

arXiv 2024年

作者： Hutchins, William Tomko, John A. Hirt, Dan M. Zare, Saman Matson, Joseph R. Diaz-Granados, Katja He, Mingze Pfeifer, Thomas Li, Jiahan Edgar, James Maria, Jon-Paul Caldwell, Joshua D. Hopkins, Patrick E. Department of Mechanical and Aerospace Engineering University of Virginia CharlottesvilleVA22904 United States Interdisciplinary Materials Science Program Vanderbilt University NashvilleTN37212 United States Department of Mechanical Engineering Vanderbilt University NashvilleTN37212 United States Tim Taylor Dept. of Chemical Engineering Kansas State University ManhattanKS United States Department of Materials Science and Engineering Pennsylvania State University University ParkPA16802 United States Department of Materials Science and Engineering University of Virginia CharlottesvilleVA22904 United States Department of Physics University of Virginia CharlottesvilleVA22904 United States

The efficiency of phonon-mediated heat transport is limited by the intrinsic atomistic properties of materials, seemingly providing an upper limit to heat transfer in materials and across their interfaces. The typical speeds of conductive transport, which are inherently limited by the chemical bonds and atomic masses, dictate how quickly heat will move in solids. Given that phonon-polaritons (PhPs), or coupled phonon-photon modes, can propagate at speeds approaching 1% of the speed of light – orders of magnitude faster than transport within a pure diffusive phonon conductor – we demonstrate that volume-confined, hyperbolic phonon-polariton (HPhP) modes supported by many biaxial polar crystals can couple energy across solid-solid interfaces at an order of magnitude higher rates than phonon-phonon conduction alone. Using pump-probe thermoreflectance with a mid-infrared, tunable, probe pulse with sub-picosecond resolution, we demonstrate remote and spectrally selective excitation of the HPhP modes in hexagonal boron nitride (hBN) in response to radiative heating from a thermally emitting gold source. Our work demonstrates a new avenue for interfacial heat transfer based on broadband radiative coupling from a hot spot in a gold film to hBN HPhPs, independent of the broad spectral mismatch between the pump (visible) and probe (mid-IR) pulses employed. This methodology can be used to bypass the intrinsically limiting phonon-phonon conductive pathway, thus providing an alternative means of heat transfer across interfaces. Further, our time-resolved measurements of the temperature changes of the HPhP modes in hBN show that through polaritonic coupling, a material can transfer heat across and away from an interface at rates orders of magnitude faster than diffusive phonon speeds intrinsic to the material, thus demonstrating a pronounced thermal transport enhancement in hBN via phonon-polariton coupling. © 2024, CC BY.

关键词： III-V semiconductors