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arXiv 2023年

作者： Rodriguez, M.C. Ranea-Sandoval, Ignacio F. Chirenti, C. Radice, D. Grupo de Gravitación Astrofísica y Cosmología Facultad de Ciencias Astronómicas y Geofísicas Universidad Nacional de La Plata Paseo del Bosque S/N La Plata1900 Argentina CONICET Godoy Cruz 2290 1425 CABA Argentina Department of Astronomy University of Maryland College ParkMD20742-2421 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 Institute for Gravitation and 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

The future detection of gravitational waves (GWs) from a galactic core-collapse supernova will provide information on the physics inside protoneutron stars (PNS). In this work, we apply three different classification methods for the PNS non-radial oscillation modes: Cowling classification, Generalized Cowling Nomenclature (GCN), and a Classification Based on Modal Properties (CBMP). Using PNS models from 3D simulations of core-collapse supernovae, we find that in the early stages of the PNS evolution, typically before 0.4 seconds after the bounce, the Cowling classification is inconsistent, but the GCN and the CBMP provide complementary information that helps to understand the evolution of the modes. In the GCN, we note several avoided crossings as the mode frequencies evolve at early times, while the CBMP tracks the modes across the avoided crossings. We verify that the strongest emission of GWs by the PNS corresponds to the f-mode in the GCN, indicating that the mode trapping region alternates between the core and the envelope at each avoided crossing. At later times, approximately 0.4 seconds after the bounce, the three classification methods present a similar description of the mode spectrum. We use our results to test universal relations for the PNS modes according to their classification and find that the behaviour of the universal relations for f- and p-modes is remarkably simple in the CBMP. Copyright © 2023, The Authors. All rights reserved.

关键词： Gravity waves

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Retina-Inspired Organic Photonic Synapses for Selective Detection of SWIR Light

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Angewandte Chemie 2022年第6期135卷

作者： Song Wang Hao Chen Tianhua Liu Yanan Wei Guo Yao Qijie Lin Xiao Han Chunfeng Zhang Hui Huang College of Materials Science and Opto-Electronic Technology Center of Materials Science and Optoelectronics Engineering CAS Center for Excellence in Topological Quantum Computation and CAS Key Laboratory of Vacuum Physics University of Chinese Academy of Sciences Beijing 100049 P.R. China National Laboratory of Solid State Microstructures School of Physics and Collaborative Innovation Center for Advanced Microstructures Nanjing University Nanjing 210093 P.R. China

Photonic synapses with the dual function of optical signal detection and information processing can simulate human visual system. However, photonic synapses with selective detection of short-wavelength infrared (SWIR) light have never been reported, which can not only broaden the human vision region but also integrate neuromorphic computation and infrared optical communication. Here, organic photonic synapses based on a new donor-acceptor copolymer P1 are fabricated, which exhibit excellent synaptic characteristics with selective detection for SWIR and extremely low energy consumption (2.85 fJ). The working mechanism is rooted in energy level barriers and unbalanced charge transportation. Moreover, these photonic synapses demonstrate excellent performance in multi-signal logic editing, letter imaging and memory with noise reduction function. This contribution provides ideas of constructing selective-response synapses for artificial visual system and neuromorphic computing.

关键词： Charge Transfer Donor-Acceptor Noise Reduction Organic Electronics Synapses

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Sensitive single-photon test of extended quantum theory with 2D hexagonal boron nitride

arXiv

引用

arXiv 2021年

作者： Vogl, Tobias Knopf, Heiko Weissflog, Maximilian Lam, Ping Koy Eilenberger, Falk Institute of Applied Physics Abbe Center of Photonics Friedrich-Schiller-Universität Jena Jena07745 Germany Cavendish Laboratory University of Cambridge JJ Thomson Avenue CambridgeCB3 0HE United Kingdom Fraunhofer-Institute for Applied Optics and Precision Engineering IOF Jena07745 Germany Max Planck School of Photonics Jena07745 Germany Centre for Quantum Computation and Communication Technology Department of Quantum Science Research School of Physics and Engineering Australian National University ActonACT2601 Australia

Quantum theory is the foundation of modern physics. Some of its basic principles, such as Born’s rule, however, are based on postulates which require experimental testing. Any deviation from Born’s rule would result in higher-order interference and can thus be tested in an experiment. Here, we report on such a test with a quantum light source based on a color center in hexagonal boron nitride (hBN) coupled to a microcavity. Our room temperature photon source features a narrow linewidth, high efficiency, high purity, and on-demand single-photon generation. With the single-photon source we can increase the interferometric sensitivity of our three-path interferometer compared to conventional laser-based light sources by fully suppressing the detector nonlinearity. We thereby obtain a tight bound on the third-order interference term of 3.96(523) × 10−4. We also measure an interference visibility of 98.58% for our single-photons emitted from hBN at room temperature, which provides a promising route for using the hBN platform as light source for phase-encoding schemes in quantum key distribution. © 2021, CC BY.

关键词： Particle beams

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Non-Fermi-liquid behavior and saddlelike flat band in the layered ferromagnet AlFe2B2

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Physical Review B 2020年第24期101卷 245129-245129页

作者： Zhonghao Liu Shuai Yang Hao Su Liqin Zhou Xiangle Lu Zhengtai Liu Jiacheng Gao Yaobo Huang Dawei Shen Yanfeng Guo Hongming Weng Shancai Wang State Key Laboratory of Functional Materials for Informatics and Center for Excellence in Superconducting Electronics Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences Shanghai 200050 China College of Materials Science and Opto-Electronic Technology University of Chinese Academy of Sciences Beijing 100049 China School of Physical Science and Technology ShanghaiTech University Shanghai 201210 China Institute of Physics and Beijing National Laboratory for Condensed Matter Physics Chinese Academy of Sciences Beijing 100190 China CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of Sciences Beijing 100049 China Shanghai Advanced Research Institute Chinese Academy of Sciences Shanghai 201204 China Department of Physics and Beijing Key Laboratory of Opto-Electronic Functional Materials & Micro-Nano Devices Renmin University of China Beijing 100872 China

AlFe2B2, a layered ferromagnet with a Curie temperature near room temperature (Tc∼270 K), has attracted growing attention recently in condensed-matter physics and materials science. Utilizing angle-resolved photoemission spectroscopy and first-principles calculations, we provide evidence of a linear band and a saddlelike flat band in the vicinity of the Fermi energy (EF) in AlFe2B2, consisting of slabs of Fe2B2 atoms separated by layers of Al. The anomalous scattering rate of the linear band varies linearly with the kinetic energy up to 120 meV, showing non-Fermi-liquid behavior consistent with T-linear dependence of resistivity. The flat band with dxy orbital character and with strong ky dispersion may be associated with spin orientation along the a axis in layered AlFe2B2. Electronic and magnetic correlation can be modulated by tuning the flat band near EF in layered ternary borides. Our findings have important implications to exploit emergent physics and quantum phases in 3d transition metals.

关键词： Electronic structure 2-dimensional systems Ferromagnets Angle-resolved photoemission spectroscopy

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Topological phase transitions of Thouless charge pumping realized in helical organic molecules with long-range hopping

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Physical Review B 2020年第15期102卷 155402-155402页

作者： Ai-Min Guo Pei-Jia Hu Xiao-Hui Gao Tie-Feng Fang Qing-Feng Sun Hunan Key Laboratory for Super-microstructure and Ultrafast Process School of Physics and Electronics Central South University Changsha 410083 China Key Laboratory for Magnetism and Magnetic Materials of MOE School of Physical Science and Technology Lanzhou University Lanzhou 730000 China International Center for Quantum Materials School of Physics Peking University Beijing 100871 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

Recent studies indicated that helical organic molecules, such as DNA and the α-helical protein, can behave as Thouless quantum pumps when a rotating electric field is applied perpendicularly to their helical axes. Here we investigate the influence of long-range hoppings on this topological pumping of electrons in single-helical organic molecules. Under variation of the long-range hoppings governed by a decay exponent μ, we find an energy gap in the molecular band structure closes at a critical value μc of the decay exponent and reopens for μ deviating from μc. The relevant bulk bands in a pumping cycle acquire different Chern numbers in the strong (μ<μc) and weak (μ>μc) long-range hopping regimes, with a sudden jump at criticality. This topological phase transition is also shown to separate two distinct behaviors of the midgap end states in the pumping process. The end states carry quantized current pumped by the rotating electric field, and the current forms a plateau by sweeping the Fermi energy over the gap. In the strong-hopping phase, the quantized current plateau is positive, which is reversed to a negative one with smaller amplitude in the weak-hopping phase. However, the reversal is a smooth crossover, not a sharp transition, due to the finite sizes of the molecules. We show that these transport characteristics of the topological phase transition could also be observed at finite temperatures.

关键词： Topological phase transition Biomolecules Topological materials

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Running of effective dimension and cosmological entropy in early universe

arXiv

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arXiv 2020年

作者： Xiao, Yong Key Laboratory of High-precision Computation and Application of Quantum Field Theory of Hebei Province College of Physical Science and Technology Hebei University Baoding071002 China Department of Physics and Astronomy University of Sussex BrightonBN1 9QH United Kingdom

In this paper, we suggest that the early universe starts from a high-energetic state with a two dimensional description and the state recovers to be four dimensional when the universe evolves into the radiation dominated phase. This scenario is consistent with the recent viewpoint that quantum gravity should be effectively two dimensional in the ultraviolet and recovers to be four dimensional in the infrared. A relationship has been established between the running of effective dimension and that of the entropy inside particle horizon of the universe, i.e., as the effective dimension runs from two to four, the corresponding entropy runs from the holographic entropy to the normal entropy appropriate to radiation. These results can be generalized to higher dimensional cases. Copyright © 2020, The Authors. All rights reserved.

关键词： Entropy

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Suppressing Exciton–Vibration Coupling via Intramolecular Noncovalent Interactions for Low-Energy-Loss Organic Solar Cells

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Angewandte Chemie 2024年第7期137卷

作者： Xiaobin Gu Yanan Wei Rui Zeng Jikai Lv Yuqi Hou Na Yu Senke Tan Zaiyu Wang Congqi Li Prof. Zheng Tang Prof. Qian Peng Prof. Feng Liu Prof. Yunhao Cai Prof. Xin Zhang Prof. Hui Huang College of Materials Science and Opto-Electronic Technology Center of Materials Science and Optoelectronics Engineering CAS Center for Excellence in Topological Quantum Computation and CAS Key Laboratory of Vacuum Physics University of Chinese Academy of Sciences Beijing 101408 China School of Chemistry and Chemical Engineering Frontiers Science Center for Transformative Molecules In situ Center for Physical Science and Center of Hydrogen Science Shanghai Jiao Tong University Shanghai 200240 China Center for Advanced Low-Dimension Materials State Key Laboratory for Modification of Chemical Fibers and Polymer Materials College of Materials Science and Engineering Donghua University Shanghai 201620 China Department of Chemistry and the Hong Kong Branch of the Chinese National Engineering Research Center for Tissue Restoration and Reconstruction The Hong Kong University of Science and Technology Hong Kong 999077 China School of Chemical Sciences University of Chinese Academy of Sciences Beijing 101408 China

Minimizing energy loss is crucial for breaking through the efficiency bottleneck of organic solar cells (OSCs). The main mechanism of energy loss can be attributed to non-radiative recombination energy loss (Δ E nr ) that occurs due to exciton–vibration coupling. To tackle this challenge, tuning intramolecular noncovalent interactions is strategically utilized to tailor novel fused ring electron acceptors (FREAs). Upon comprehensive analysis of both theoretical and experimental results, this approach can effectively enhance molecular rigidity, suppress structural relaxation, reduce exciton reorganization energy, and weakens exciton–vibration coupling strength. Consequently, the binary OSC device based on Y-SeSe, which features dual strong intramolecular Se ⋅ ⋅ ⋅ O noncovalent interactions, achieves an outstanding power conversion efficiency (PCE) of 19.49 %, accompanied by an extremely small Δ E nr of 0.184 eV, much lower than those of Y-SS and Y-SSe based devices with weaker intramolecular noncovalent interactions. These achievements not only set an efficiency record for selenium-containing OSCs, but also mark the lowest reported Δ E nr value among high-performance binary devices. Furthermore, the ternary blend device showcases a remarkable PCE of 20.51 %, one of the highest PCEs for single-junction OSCs. This work demonstrates the effectiveness of intramolecular noncovalent interactions in suppressing exciton–vibration coupling, thereby achieving low-energy-loss and high-efficiency OSCs.

关键词： organic solar cells non-radiative recombination energy loss intramolecular noncovalent interactions molecular rigidity exciton–vibration coupling

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Valley population of donor states in highly strained silicon

arXiv

引用

arXiv 2021年

作者： Voisin, B. Ng, K.S.H. Salfi, J. Usman, M. Wong, J.C. Tankasala, A. Johnson, B.C. McCallum, J.C. Hutin, L. Bertrand, B. Vinet, M. Valanoor, N. Simmons, M.Y. Rahman, R. Hollenberg, L.C.L. Rogge, S. Silicon Quantum Computing SydneyNSW2052 Australia School of Physics Sydney The University of New South Wales SydneyNSW2052 Australia Centre for Quantum Computation and Communication Technology School of Physics The University of New South Wales SydneyNSW2052 Australia 5. Physikalisches Institut and Center for Integrated Quantum Science and Technology Universität Stuttgart Stuttgart70569 Germany Department of Electrical and Computer Engineering University of British Columbia VancouverBCV6T 1Z4 Canada Centre for Quantum Computation and Communication Technology School of Physics The University of Melbourne ParkvilleVIC3010 Australia School of Computing and Information Systems Faculty of Engineering and Information Technology The University of Melbourne ParkvilleVIC3010 Australia School of Materials Science and Engineering The University of New South Wales SydneyNSW2052 Australia Electrical and Computer Engineering Department Purdue University West LafayetteIN United States Quantum Photonics Laboratory School of Engineering RMIT University MelbourneVIC3000 Australia Université Grenoble Alpes CEA LETI Grenoble38000 France

Strain is extensively used to controllably tailor the electronic properties of materials. In the context of indirect band-gap semiconductors such as silicon, strain lifts the valley degeneracy of the six conduction band minima, and by extension the valley states of electrons bound to phosphorus donors. Here, single phosphorus atoms are embedded in an engineered thin layer of silicon strained to 0.8% and their wave function imaged using spatially resolved spectroscopy. A prevalence of the out of plane valleys is confirmed from the real-space images, and a combination of theoretical modelling tools is used to assess how this valley repopulation effect can yield isotropic exchange and tunnel interactions in the xy-plane relevant for atomically precise donor qubit devices. Finally, the residual presence of in-plane valleys is evidenced by a Fourier analysis of both experimental and theoretical images, and atomistic calculations highlight the importance of higher orbital excited states to obtain a precise relationship between valley population and strain. Controlling the valley degree of freedom in engineered strained epilayers provides a new competitive asset for the development of donor-based quantum technologies in silicon. Copyright © 2021, The Authors. All rights reserved.

关键词： Landforms

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Sulfur vs. tellurium: the heteroatom effects on the nonfullerene acceptors

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science China Chemistry 2019年第7期62卷 897-903页

作者： Lei Yang Linqing Qin Yunxiao Xu Huotian Zhang Lei Lv Kepeng Chen Xinyu Sui Yangguang Zhong Yuan Guo Feng Gao Jianzhang Zhao Yuhao Li Xinfeng Liu Yuanping Yi Xinhui Lu Aidong Peng Hui Huang College of Materials Science and Optoelectronic Technology Center of Materials Science and Optoelectronics Engineering CAS Center for Excellence in Topological Quantum Computation CAS Key Laboratory of Vacuum Physic University of Chinese Academy of Sciences Beijing 101408 China Department of Chemical Engineering Imperial College London London SW7 24Z United Kingdom Biomolecular and Organic Electronics Department of Physics Chemistry and Biology (IFM) Linkoping University Linkuping SE-58183 Sweden Division of Nanophotonics CAS Key Laboratory of Standardization and Measurement for Nanotechnology CAS Center for Excellence in Nanoscience National Center for Nanoscience and Technology Beijing 100190 China University of Chinese Academy of Sciences Beijing 100049 China State Key Laboratory of Fine Chemicals School of Chemical Engineering Dalian University of Technology Dalian 116024 China Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Organic Solids CAS Research/Education Center for Excellence in Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100190 China Department of Physics The Chinese University of Hong Kong Shatin NT 999077 Hong Kong China

The effect of chalcogen heteroatom variation on donor materials has been systematically investigated. However, this effect on acceptors has rarely been explored. Herein, nonfullerene acceptors BFPSP and BFPTP were reported by simply changing the chalcogen atoms from S to Te. The differences between BFPSP and BFPTP in light absorption, energy levels, excited-state lifetimes, energy loss, charge mobilities, morphology, and photovoltaic properties were systematically investigated to understand the heteroatom effects. More importantly, the electroluminescence spectra, external quantum efficiency of photovoltaics and TDDFTcalculations revealed that the triplet excited state(T1) in energy of BFPTP equals to the charge transfer(CT) state in PBDBT:BFPTP, which allows T1 excitons, generated by intersystem crossing, to split into free charges to contribute to the *** contribution provides a strategy for tuning the photophysical properties of nonfullerene acceptors and designing high performance triplet materials for OSCs.

关键词： heteroatom effects triplet state tellurophene nonfullerene acceptor organic solar cells

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DARK SAGE: Next-generation semi-analytic galaxy evolution with multidimensional structure and minimal free parameters

arXiv

引用

arXiv 2023年

作者： Stevens, Adam R.H. Sinha, Manodeep Rohl, Alexander Sammons, Mawson W. Hadzhiyska, Boryana Hernández-Aguayo, César Hernquist, Lars International Centre for Radio Astronomy Research The University of Western Australia CrawleyWA6009 Australia Australia Centre for Astrophysics and Supercomputing Swinburne University of Technology HawthornVIC3122 Australia School of Computer and Mathematical Sciences The University of Adelaide AdelaideSA5000 Australia Department of Mathematics and Statistics The University of Western Australia CrawleyWA6009 Australia International Centre for Radio Astronomy Research Curtin University BentleyWA6102 Australia Miller Institute for Basic Research in Science University of California BerkeleyCA94720 United States Physics Division Lawrence Berkeley National Laboratory BerkeleyCA94720 United States Max-Planck-Institut für Astrophysik Garching BayernD-85741 Germany Institute for Theory and Computation Harvard–Smithsonian Center for Astrophysics CambridgeMA02138 United States

After more than five years of development, we present a new version of Dark Sage, a semi-analytic model (SAM) of galaxy formation that breaks the mould for models of its kind. Included among the major changes is an overhauled treatment of stellar feedback that is derived from energy conservation, operates on local scales, affects gas gradually over time rather than instantaneously, and predicts a mass-loading factor for every galaxy. Building on the model’s resolved angular-momentum structure of galaxies, we now consider the heating of stellar discs, delivering predictions for disc structure both radially and vertically. We add a further dimension to stellar discs by tracking the distribution of stellar ages in each annulus. Each annulus–age bin has its own velocity dispersion and metallicity evolved in the model. This allows Dark Sage to make structural predictions for galaxies that previously only hydrodynamic simulations could. We present the model as run on the merger trees of the highest-resolution gravity-only simulation of the MillenniumTNG suite. Despite its additional complexity relative to other SAMs, Dark Sage only has three free parameters, the least of any SAM, which we calibrate exclusively against the cosmic star formation history and the z = 0 stellar and H i mass functions using a particle-swarm optimisation method. The Dark Sage codebase, written in C and python, is publicly available at https://***/arhstevens/DarkSage. Copyright © 2023, The Authors. All rights reserved.

关键词： Galaxies

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