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Quantum 2.0, QUANTUM 2022

作者： Davis, Samantha I. Mueller, Andrew Valivarthi, Raju Lauk, Nikolai Narvaez, Lautaro Korzh, Boris Beyer, Andrew D. Colangelo, Marco Berggren, Karl K. Shaw, Matthew D. Sinclair, Neil Spiropulu, Maria Division of Physics Mathematics and Astronomy California Institute of Technology 1200 E California Blvd. PasadenaCA91125 United States California Institute of Technology 1200 E California Blvd. PasadenaCA91125 United States Jet Propulsion Laboratory California Institute of Technology 4800 Oak Grove Dr. PasadenaCA91109 United States Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology 50 Vassar St. CambridgeMA02139 United States John A. Paulson School of Engineering and Applied Sciences Harvard University 29 Oxford St. CambridgeMA02138 United States

We experimentally demonstrate an improved heralded single photon source using a photon-number-resolving superconducting nanowire detector compared to that using a conventional bucket detector. This work delineates a p... 详细信息

ISBN: (纸本)9781957171111

关键词： Photons

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Soft-mode enhanced type-I superconductivity in LiPd2Ge

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Physical Review B 2020年第2期102卷 024507-024507页

作者： Karolina Górnicka Gabriel Kuderowicz Elizabeth M. Carnicom Kamil Kutorasiński Bartlomiej Wiendlocha Robert J. Cava Tomasz Klimczuk Faculty of Applied Physics and Mathematics and Advanced Materials Centre Gdansk University of Technology Narutowicza 11/12 80-233 Gdańsk Poland Faculty of Physics and Applied Computer Science AGH University of Science and Technology Aleja Mickiewicza 30 30-059 Kraków Poland Department of Chemistry Princeton University Princeton New Jersey 08544 USA

The synthesis, crystal structure, and physical properties (magnetization, resistivity, heat capacity) in combination with theoretical calculations of the electronic structure and phonon properties are reported for intermetallic compounds LiPd2X (X=Si, Ge, and Sn). LeBail refinement of powder x-ray diffraction data confirms that all compounds belong to the Heusler family (space group Fm−3m, No. 225). The lattice parameter increases with atomic size of X, and its value varies from a=5.9059(4)Å for LiPd2Si and a=6.0082(3)Å for LiPd2Ge, to a=6.2644(1)Å for LiPd2Sn. The first compound, LiPd2Si, has apparently not been previously reported. All measured quantities demonstrate that LiPd2Ge exhibits superconductivity below Tc=1.96K and the normal- and superconducting-state data indicate that it is a weak-strength type-I superconductor (C/γTc=1.38) with electron-phonon coupling constant λe−p=(0.53−0.56). LiPd2Si and LiPd2Sn are not superconducting above 1.68 K. The experimental observations are supported by theoretical calculations which show that LiPd2Ge has the highest computed λe−p and Tc of the group. A strong softening of the acoustic phonon mode is calculated, and in the case of X=Ge and Sn, imaginary phonon frequencies were computed. The soft mode is most pronounced in the case of LiPd2Ge, which suggests its correlation with superconductivity.

关键词： Superconductivity Heusler alloy Low-temperature superconductors DC susceptibility measurements Electrical techniques First-principles calculations Specific heat measurements X-ray powder diffraction

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Modular A4 symmetry and light dark matter with gauged U(1)B−L

arXiv

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arXiv 2021年

作者： Nagao, Keiko I. Okada, Hiroshi Okayama University of Science Faculty of Science Department of Applied Physics Ridaicho 1-1 Okayama700-0005 Japan - Headquarters San 31 Hyoja-dong Nam-gu Pohang790-784 Korea Republic of Department of Physics Pohang University of Science and Technology Pohang37673 Korea Republic of

We propose a radiative seesaw model with a light dark matter candidate (DM) under modular A4 and gauged U(1)B−L symmetries, in which neutrino masses are generated via one-loop level, and we have a bosonic DM candidate ∼ 0.01 − 50 GeV. DM is stabilized by nonzero modular weight and a remnant Z2 symmetry of U(1)B−L symmetry. The naturalness of tiny DM mass is indirectly realized by the radiatively induced mass of neutral fermions that interact with our DM candidate. Thus, DM mass does not have to exceed the neutral fermion masses, whose scale is assumed to be 50 GeV. Taking several benchmark points of DM mass in DM analysis, we show the numerical analysis for the neutrino oscillation data in the normal and inverted hierarchy cases and find several features for both cases. © 2021, CC0.

关键词： Galaxies

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Particle Swarm Optimization and L´evy Flight integration

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Procedia computer science 2021年 192卷 4658-4671页

作者： Joanna Kołodziejczyk Yuliia Tarasenko Research Team on Intelligent Decision Support Systems Department of Artificial Intelligence Methods and Applied Mathematics Faculty of Computer Science and Information Technology West Pomeranian University of Technology in Szczecin ul. Żołnierska 49 71-210 Szczecin Poland

Particle Swarm Optimization (PSO) is a well-known and popular stochastic optimization method. The Lévy Flight (LF) properties were used to improve the canonical PSO known as premature convergence. The Lévy Flight was applied to change each particle walk on the fitness landscape. We analyze the literature modifications that concluded that Levy flight improved the PSO providing better search space exploration. Based on this conclusion, we propose new approaches to integrate Lévy Flight with PSO by changing initial points in the search space and learning strategies as inertia and constriction coefficients. We use seven standard test functions for an experimental evaluation and scores based on ranking to compare PSO variants. The ranked benchmarks were average performance, standard deviation, and best and worst found solutions obtained from multiple trials. The main contributions are a systematic overview of LF modifications applied in PSO and three new LF applications in canonical PSO procedure. The new approaches are swarm initialization based on LF, lower dimension LF inertia coefficient, and LF-based constriction factor. Another contribution is numerical evaluations on various benchmark functions with diverse characteristics. Two of the proposed modifications performed better or equal, and the third was only 2% worse than the best canonical PSO from the trial.

关键词： Particle Swarm Optimization Lévy Flight stochastic optimization

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From predictions to decisions: using lookahead regularization 20

From predictions to decisions: using lookahead regularizatio...

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Proceedings of the 34th International Conference on Neural Information Processing Systems

作者： Nir Rosenfeld Sophie Hilgard Sai S. Ravindranath David C. Parkes Faculty of Computer Science Technion - Israel Institute of Technology School of Engineering and Applied Science Harvard University

ISBN: (纸本)9781713829546

Machine learning is a powerful tool for predicting human-related outcomes, from creditworthiness to heart attack risks. But when deployed transparently, learned models also affect how users act in order to improve outcomes. The standard approach to learning predictive models is agnostic to induced user actions and provides no guarantees as to the effect of actions. We provide a framework for learning predictors that are accurate, while also considering interactions between the learned model and user decisions. For this, we introduce look-ahead regular-ization which, by anticipating user actions, encourages predictive models to also induce actions that improve outcomes. This regularization carefully tailors the uncertainty estimates that govern confidence in this improvement to the distribution of model-induced actions. We report the results of experiments on real and synthetic data that show the effectiveness of this approach.

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INTERACTING PARTICLE SYSTEMS WITH CONTINUOUS SPINS

arXiv

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arXiv 2023年

作者： Bezborodov, Viktor Di Persio, Luca Friesen, Martin Kuchling, Peter Institute for Mathematical Stochastics Georg-August-University of Goettingen Goldschmidtstraße 7 Goettingen37077 Germany Wroclaw University of Science and Technology Faculty of Electronics ul. Janiszewskiego 11/17 Wroclaw50-372 Poland Department of Computer Science University of Verona Strada le Grazie 15 Verona Italy School of Mathematical Sciences Dublin City University Glasnevin Dublin 9 Ireland Hochschule Bielefeld - University of Applied Sciences and Arts Germany

We study a general class of interacting particle systems over a countable state space V where on each site x ∈ V the particle mass η(x) ≥ 0 follows a stochastic differential equation. We construct the corresponding Markovian dynamics in terms of strong solutions to an infinite coupled system of stochastic differential equations and prove a comparison principle with respect to the initial configuration as well as the drift of the process. Using this comparison principle, we provide sufficient conditions for the existence and uniqueness of an invariant measure in the subcritical regime and prove convergence of the transition probabilities in the Wasserstein-1-distance. Finally, for sublinear drifts, we establish a linear growth theorem showing that the spatial spread is at most linear in time. Our results cover a large class of finite and infinite branching particle systems with interactions among different sites. Copyright © 2023, The Authors. All rights reserved.

关键词： Stochastic systems

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Heralding Single Photons using Photon-number-resolving Superconducting Nanowires

Heralding Single Photons using Photon-number-resolving Super...

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CLEO: QELS_Fundamental science, QELS 2022

ISBN: (纸本)9781557528209

We improve a single photon source based on spontaneous parametric down-conversion by heralding one of the output modes using a photon number resolving superconducting nanowire detector. We measure a reduced magnitude of the second order cross correlation of one of the output modes conditioned on detection of a single photon in the other mode. © Optica Publishing Group 2022, © 2022 The Author(s)

关键词： Photons

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Levenberg-Marquardt Backpropagation for Numerical Treatment of Micropolar Flow in a Porous Channel with Mass Injection

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Complexity 2021年第1期2021卷

作者： Ullah, Hakeem Khan, Imran Alsalman, Hussain Islam, Saeed Asif Zahoor Raja, Muhammad Shoaib, Muhammad Gumaei, Abdu Fiza, Mehreen Ullah, Kashif Mizanur Rahman, Sk. Md. Ayaz, Muhammad Department of Mathematics Abdul Wali Khan University Mardan MardanKP 23200 Pakistan Department of Computer Science College of Computer and Information Sciences King Saud University Riyadh11543 Saudi Arabia Future Technology Research Center National Yunlin University of Science and Technology 123 University Road Section 3 Douliou Yunlin64002 Taiwan Department of Mathematics COMSATS University Islamabad Attock Campus Attock43600 Pakistan Department of Computer Science Faculty of Applied Sciences Taiz University Taiz6803 Yemen Information and Communication Engineering Technology School of Engineering Technology and Applied Science Centennial College Toronto Canada

In this research work, an effective Levenberg-Marquardt algorithm-based artificial neural network (LMA-BANN) model is presented to find an accurate series solution for micropolar flow in a porous channel with mass injection (MPFPCMI). The LMA is one of the fastest backpropagation methods used for solving least-squares of nonlinear problems. We create a dataset to train, test, and validate the LMA-BANN model regarding the solution obtained by optimal homotopy asymptotic (OHA) method. The proposed model is evaluated by conducting experiments on a dataset acquired from the OHA method. The experimental results are obtained by using mean square error (MSE) and absolute error (AE) metric functions. The learning process of the adjustable parameters is conducted with efficacy of the LMA-BANN model. The performance of the developed LMA-BANN for the modelled problem is confirmed by achieving the best promise numerical results of performance in the range of E-05 to E-08 and also assessed by error histogram plot (EHP) and regression plot (RP) measures. © 2021 Hakeem Ullah et al.

关键词： Mean square error

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Author Correction: Engineering holography with stabilizer graph codes

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npj Quantum Information 2024年第1期10卷 1页

作者： Gerard Anglès Munné Felix Huber Valentin Kasper Faculty of Physics Astronomy and Applied Computer Science Institute of Theoretical Physics Jagiellonian University 30-348 Kraków Poland Bordeaux Computer Science Laboratory (LaBRI) University of Bordeaux 351 cours de la Liberation 33405 Talence France Institut de Ciéncies Fotóniques (ICFO) Mediterranean Technology Park 08860 Castelldefels Barcelona Spain

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Charge order above room-temperature in a prototypical kagome superconductor La(Ru1−xFex)3Si2

arXiv

引用

arXiv 2023年

作者： Plokhikh, I. Mielke, C. Nakamura, H. Petricek, V. Qin, Y. Sazgari, V. Küspert, J. Bialo, I. Shin, S. Ivashko, O. Zimmermann, M.V. Medarde, M. Amato, A. Khasanov, R. Luetkens, H. Fischer, M.H. Hasan, M.Z. Yin, J.-X. Neupert, T. Chang, J. Xu, G. Nakatsuji, S. Pomjakushina, E. Gawryluk, D.J. Guguchia, Z. Laboratory for Multiscale Materials Experiments Paul Scherrer Institut Villigen PSICH-5232 Switzerland Laboratory for Muon Spin Spectroscopy Paul Scherrer Institute Villigen PSICH-5232 Switzerland Physik-Institut Universität Zürich Winterthurerstrasse 190 ZürichCH-8057 Switzerland University of Tokyo Chiba Kashiwa277-8581 Japan Institute of Physics CAS Na Slovance 1999/2 Praha Czech Republic Wuhan National High Magnetic Field Center School of Physics Huazhong University of Science and Technology Wuhan430074 China AGH University of Science and Technology Faculty of Physics and Applied Computer Science Kraków30-059 Poland Laboratory for Multiscale Materials Experiments Paul Scherrer Institut Villigen PSI5232 Switzerland Deutsches Elektronen-Synchrotron DESY Notkestraße 85 Hamburg22607 Germany Department of Physics Princeton University PrincetonNJ08544 United States

The kagome lattice [1] is an intriguing and rich platform [2–5] for discovering, tuning and understanding the diverse phases of quantum matter, which is a necessary premise for utilizing quantum materials in all areas of modern and future electronics in a controlled and optimal way. The system LaRu3Si2 [6, 7] was shown to exhibit typical kagome band structure features near the Fermi energy formed by the Ru-dz2 orbitals [8] and the highest superconducting transition temperature Tc 7 K among the kagome-lattice materials. However, the effect of electronic correlations on the normal state properties remains elusive. Here, we report the discovery of charge order in La(Ru1−xFex)3Si2 (x = 0, 0.01, 0.05) beyond room-temperature. Namely, single crystal X-ray diffraction reveals charge order with a propagation vector of (1/4, 0, 0) below TCO−I 400 K in all three compounds. At lower temperatures, we see the appearance of a second set of charge order peaks with a propagation vector of (1/6, 0, 0). The introduction of Fe, which is known to quickly suppress superconductivity [8], does not drastically alter the onset temperature for charge order. Instead, it broadens the scattered intensity such that diffuse scattering appears at the same onset temperature, however does not coalesce into sharp Bragg diffrac- tion peaks until much lower in temperature. Our results present the first example of a charge ordered state at or above room temperature in the correlated kagome lattice with bulk superconductivity. Copyright © 2023, The Authors. All rights reserved.

关键词： Room temperature

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