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arXiv 2024年

作者： Harkins, Kieren A. Selco, Cooper Bengs, Christian Marchiori, David Moon, Leo Joon Il Zhang, Zhuo-Rui Yang, Aristotle Singh, Angad Druga, Emanuel Song, Yi-Qiao Ajoy, Ashok Department of Chemistry University of California Berkeley BerkeleyCA94720 United States Chemical Sciences Division Lawrence Berkeley National Laboratory BerkeleyCA94720 United States John A. Paulson School of Engineering and Applied Sciences Harvard University CambridgeMA02138 United States CIFAR Azrieli Global Scholars Program 661 University Ave TorontoONM5G 1M1 Canada

Floquet prethermalization is observed in periodically driven quantum many-body systems where the system avoids heating and maintains a stable, non-equilibrium state, for extended periods. Here we introduce a novel quantum control method using off-resonance and short-angle excitation to significantly extend Floquet prethermal lifetimes. This is demonstrated on randomly positioned, dipolar-coupled, 13C nuclear spins in diamond, but the methodology is broadly applicable. We achieve a lifetime T2′≈800 s at 100 K while tracking the transition to the prethermal state quasi-continuously. This corresponds to a >533,000-fold extension over the bare spin lifetime without prethermalization, and constitutes a new record both in terms of absolute lifetime as well as the total number of Floquet pulses applied (here exceeding 7 million). Using Laplace inversion, we develop a new form of noise spectroscopy that provides insights into the origin of the lifetime extension. Finally, we demonstrate applications of these extended lifetimes in long-time, reinitialization-free quantum sensing of time-varying magnetic fields continuously for ∼10 minutes at room temperature. Our work facilitates new opportunities for stabilizing driven quantum systems through Floquet control, and opens novel applications for continuously interrogated, long-time responsive quantum sensors. © 2024, CC BY.

关键词： Quantum optics

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Expansion cooling prospects for large scale applications

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International Journal of Thermofluids 2023年 20卷

作者： Alami, Abdul Hai Alrashid, Rashid Mdallal, Ayman Yasin, Ahmad Ayoub, Mohamad Alasad, Shamma Aljaghoub, Haya Alashkar, Adnan Abdelkareem, Mohammad Ali Olabi, Abdul Ghani Orhan, Mehmet Department of Sustainable and Renewable Energy Engineering University of Sharjah P.O. Box 27272 Sharjah United Arab Emirates Sustainable Energy and Power Systems Research Centre RISE University of Sharjah P.O. Box 27272 Sharjah United Arab Emirates Department of Mechanical Engineering American University of Sharjah P.O. Box 26666 Sharjah United Arab Emirates Department of Mechatronics Engineering American University of Sharjah P.O. Box 26666 Sharjah United Arab Emirates Department of Industrial Engineering and Engineering Management University of Sharjah P.O. Box 27272 Sharjah United Arab Emirates Materials Science and Engineering PhD Program American University of Sharjah P.O. Box 26666 Sharjah United Arab Emirates Chemical Engineering Department Minia University Elminia Egypt Mechanical Engineering and Design School of Engineering and Applied Science Aston University Aston Triangle BirminghamB4 7ET United Kingdom

Air conditioning in general and cooling in particular are the biggest energy sinks among all electricity consumers. Mitigating energy needs of this sector by active or passive means is a necessity. This paper offers a comprehensive review of various cooling technologies for large scale applications and compares them in terms of economy, environmental footprint and most importantly, energy requirements. There is a main focus on the potential of using expansion cooling, which is defined in conjunction with cooling effects generated during the expansion process of a gas. The interest in such cooling technology stems from the double benefit of utilizing a large-scale compressed air energy storage (CAES) system that can also provide cooling via the expansion of air. This consequently manifests in reducing the electrical demand required for cooling applications. Such a concept is beneficial for hot climates, where most of the electrical demand is reserved for offsetting the cooling load. © 2023 The Author(s)

关键词： Compressed air energy storage

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DPA-2:a large atomic model as a multitask learner

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npj Computational Materials 2024年第1期10卷 185-199页

作者： Duo Zhang Xinzijian Liu Xiangyu Zhang Chengqian Zhang Chun Cai Hangrui Bi Yiming Du Xuejian Qin Anyang Peng Jiameng Huang Bowen Li Yifan Shan Jinzhe Zeng Yuzhi Zhang Siyuan Liu Yifan Li Junhan Chang Xinyan Wang Shuo Zhou Jianchuan Liu Xiaoshan Luo Zhenyu Wang Wanrun Jiang Jing Wu Yudi Yang Jiyuan Yang Manyi Yang Fu-Qiang Gong Linshuang Zhang Mengchao Shi Fu-Zhi Dai Darrin M.York Shi Liu Tong Zhu Zhicheng Zhong Jian Lv Jun Cheng Weile Jia Mohan Chen Guolin Ke Weinan E Linfeng Zhang Han Wang AI for Science Institute BeijingP.R.China DP Technology BeijingP.R.China Academy for Advanced Interdisciplinary Studies Peking UniversityBeijingP.R.China State Key Lab of Processors Institute of Computing TechnologyChinese Academy of SciencesBeijingP.R.China University of Chinese Academy of Sciences BeijingP.R.China HEDPS CAPTCollege of EngineeringPeking UniversityBeijingP.R.China Ningbo Institute of Materials Technology and Engineering Chinese Academy of SciencesNingboP.R.China CAS Key Laboratory of Magnetic Materials and Devices and Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology Chinese Academy of SciencesNingboP.R.China School of Electronics Engineering and Computer Science Peking UniversityBeijingP.R.China Shanghai Engineering Research Center of Molecular Therapeutics&New Drug Development School of Chemistry and Molecular EngineeringEast China Normal UniversityShanghaiP.R.China Laboratory for Biomolecular Simulation Research Institute for Quantitative Biomedicine and Department of Chemistry and Chemical BiologyRutgers UniversityPiscatawayNJUSA Department of Chemistry Princeton UniversityPrincetonNJUSA College of Chemistry and Molecular Engineering Peking UniversityBeijingP.R.China Yuanpei College Peking UniversityBeijingP.R.China School of Electrical Engineering and Electronic Information Xihua UniversityChengduP.R.China State Key Laboratory of Superhard Materials College of PhysicsJilin UniversityChangchunP.R.China Key Laboratory of Material Simulation Methods&Software of Ministry of Education College of PhysicsJilin UniversityChangchunP.R.China International Center of Future Science Jilin UniversityChangchunP.R.China Key Laboratory for Quantum Materialsof Zhejiang Province Department of PhysicsSchool of ScienceWestlake UniversityHangzhouP.R.China Atomistic Simulations Italian Institute of TechnologyGenovaItaly State Key Laboratory of Physical Chemistry of Solid Surface iChEMCollege of Chemistry and Chemical EngineeringXiame

The rapid advancements in artificial intelligence(AI)are catalyzing transformative changes in atomic modeling,simulation,and ***-driven potential energy models havedemonstrated the capability to conduct large-scale,long-duration simulations with the accuracy of ab initio electronic structure ***,the model generation process remains a bottleneck for large-scale *** propose a shift towards a model-centric ecosystem,wherein a large atomic model(LAM),pretrained across multiple disciplines,can be efficiently fine-tuned and distilled for various downstream tasks,thereby establishing a new framework for molecular *** this study,we introduce the DPA-2 architecture as a prototype for ***-trained on a diverse array of chemical and materials systemsusing a multi-task approach,DPA-2demonstrates superior generalization capabilities across multiple downstream tasks compared to the traditional single-task pre-training and fine-tuning *** approach sets the stage for the development and broad application of LAMs in molecular and materials simulation research.

关键词： DPA establishing thereby

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Preparation of Thermally Stable 3-Glycidyloxypropyl-Poss-Derived Polysilsesquioxane Ro Membranes for Water Desalination

SSRN

引用

SSRN 2022年

作者： Zhang, Dian Kanezashi, Masakoto Tsuru, Toshinori Yamamoto, Kazuki Gunji, Takahiro Adachi, Yohei Ohshita, Joji Smart Innovation Program Graduate School of Advanced Science and Engineering Hiroshima University Higashi-Hiroshima739-8527 Japan Chemical Engineering Program Graduate School of Advanced Science and Engineering Hiroshima University Higashi-Hiroshima739-8527 Japan Department of Pure and Applied Chemistry Faculty of Science and Technology Tokyo University of Science Chiba278-8510 Japan Education and Research Center Hiroshima University Higashi-Hiroshima739-0046 Japan

Reverse osmosis (RO) membranes with polysilsesquioxane (PSQ) framework having high NaCl rejection and favorable resistance to heat and chlorine were prepared by the copolymerization of 3-glycidyloxypropyl-POSS (GPOSS) and bis[3-(triethoxysilyl)propyl]amine (BTESPA). It was found that NaCl rejection and liquid permeability were significantly improved by the introduction of GPOSS-derived units to the BTESPA-based membranes, yielding NaCl rejection of approximately 99% and liquid permeability of 5.5 × 10 -13 m/s·Pa. These PSQ RO membranes with GPOSS-derived units also demonstrated excellent resistance to heat treatment of up to 100 °C and favorable resistance to chlorine in that no obvious RO performance change was observed after exposure to NaOCl aqueous solution (1000 ppm) for 10 h. © 2022, The Authors. All rights reserved.

关键词： Desalination

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Uniqueness of weak solutions to the primitive equations in some anisotropic spaces

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Journal of Differential Equations 2025年 444卷

作者： Tim Binz Yoshiki Iida Program in Applied and Computational Mathematics Princeton University Fine Hall Washington Road Princeton 08544 NJ the United States of America Department of Pure and Applied Mathematics Graduate School of Fundamental Science and Engineering Waseda University Okubo 3-4-1 Shinjuku-ku Tokyo 169-8555 Japan

We consider the both 3D and 2D viscous primitive equations for ocean in the isothermal setting. While strong global well-posedness of the viscous primitive equations for large data in H 1 has already proved, the uniqueness of the weak solutions of Leray–Hope type for given initial data in L 2 remains an outstanding open problem. In this paper, we establish a new conditional uniqueness result for weak solutions to the primitive equations, that is, if a weak solution belongs some scaling invariant function spaces, and satisfies some additional assumptions, then the weak solution is unique. In particular, our result can be obtained as different one from z -weak solutions framework by adopting some anisotropic approaches with the homogeneous toroidal Besov spaces. As an application of the proof, we establish the energy equality for weak solutions in the uniqueness class given in the main theorem.

关键词： 35Q86 35K59 86A05 86A10 35Q35 Primitive equations Conditional uniqueness Anisotropic spaces Besov spaces Scaling invariance

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Quantum Linear System Solvers: A Survey of Algorithms and Applications

arXiv

引用

arXiv 2024年

作者： Morales, Mauro E.S. Pira, Lirandë Schleich, Philipp Koor, Kelvin Costa, Pedro C.S. An, Dong Aspuru-Guzik, Alán Lin, Lin Rebentrost, Patrick Berry, Dominic W. Joint Center for Quantum Information and Computer Science University of Maryland United States Centre for Quantum Software and Information University of Technology Sydney Australia Centre for Quantum Technologies National University of Singapore Singapore Department of Computer Science University of Toronto Canada Vector Institute for Artificial Intelligence Toronto Canada ContinoQuantum Sydney Australia Beijing International Center for Mathematical Research Peking University Beijing China Department of Chemistry University of Toronto Canada Canadian Institute for Advanced Research Toronto Canada Acceleration Consortium Toronto Canada Department of Chemical Engineering & Applied Chemistry University of Toronto Toronto Canada Department of Materials Science & Engineering University of Toronto Toronto Canada Lebovic Fellow Canadian Institute for Advanced Research Toronto Canada Department of Mathematics University of California Berkeley United States Applied Mathematics and Computational Research Division Lawrence Berkeley National Laboratory Berkeley United States Department of Computer Science National University of Singapore Singapore School of Mathematical and Physical Sciences Macquarie University Sydney Australia

Solving linear systems of equations plays a fundamental role in numerous computational problems from different fields of science. The widespread use of numerical methods to solve these systems motivates investigating the feasibility of solving linear systems problems using quantum computers. In this work, we provide a survey of the main advances in quantum linear systems algorithms, together with some applications. We summarize and analyze the main ideas behind some of the algorithms for the quantum linear systems problem in the literature. The analysis begins by examining the Harrow-Hassidim-Lloyd (HHL) solver. We note its limitations and reliance on computationally expensive quantum methods, then highlight subsequent research efforts which aimed to address these limitations and optimize runtime efficiency and precision via various paradigms. We focus in particular on the post-HHL enhancements which have paved the way towards optimal lower bounds with respect to error tolerance and condition number. By doing so, we propose a taxonomy that categorizes these studies. Furthermore, by contextualizing these developments within the broader landscape of quantum computing, we explore the foundational work that have inspired and informed their development, as well as subsequent refinements. Finally, we discuss the potential applications of these algorithms in differential equations, quantum machine learning, and many-body physics. © 2024, CC BY.

关键词： Quantum computers

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Biwhitening reveals the rank of a count matrix

arXiv

引用

arXiv 2021年

作者： Landa, Boris Zhang, Thomas T.C.K. Kluger, Yuval Program in Applied Mathematics Yale University United States Department of Electrical and Systems Engineering University of Pennsylvania United States Interdepartmental Program in Computational Biology and Bioinformatics Yale University United States Department of Pathology Yale University School of Medicine United States

Estimating the rank of a corrupted data matrix is an important task in data analysis, most notably for choosing the number of components in PCA. Significant progress on this task was achieved using random matrix theory by characterizing the spectral properties of large noise matrices. However, utilizing such tools is not straightforward when the data matrix consists of count random variables, e.g., Poisson, in which case the noise can be heteroskedastic with an unknown variance in each entry. In this work, we consider a Poisson random matrix with independent entries, and propose a simple procedure termed biwhitening for estimating the rank of the underlying signal matrix (i.e., the Poisson parameter matrix) without any prior knowledge. Our approach is based on the key observation that one can scale the rows and columns of the data matrix simultaneously so that the spectrum of the corresponding noise agrees with the standard Marchenko-Pastur (MP) law, justifying the use of the MP upper edge as a threshold for rank selection. Importantly, the required scaling factors can be estimated directly from the observations by solving a matrix scaling problem via the Sinkhorn-Knopp algorithm. Aside from the Poisson, our approach is extended to families of distributions that satisfy a quadratic relation between the mean and the variance, such as the generalized Poisson, binomial, negative binomial, gamma, and many others. This quadratic relation can also account for missing entries in the data. We conduct numerical experiments that corroborate our theoretical findings, and showcase the advantage of our approach for rank estimation in challenging regimes. Furthermore, we demonstrate the favorable performance of our approach on several real datasets of single-cell RNA sequencing (scRNA-seq), High-Throughput Chromosome Conformation Capture (Hi-C), and document topic *** Codes 62H12, 62H25. Copyright © 2021, The Authors. All rights reserved.

关键词： Random variables

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More Optimal Fractional-Order Stochastic Gradient Descent for Non-Convex Optimization Problems

arXiv

引用

arXiv 2025年

作者： Partohaghighi, Mohammad Marcia, Roummel Chen, YangQuan Electrical Engineering and Computer Science Graduate Program University of California Merced United States Department of Applied Mathematics University of California Merced MercedCA United States Lab Department of Mechanical Engineering School of Engineering University of California MercedCA95343 United States

Fractional-order stochastic gradient descent (FOSGD) leverages fractional exponents to capture long-memory effects in optimization. However, its utility is often limited by the difficulty of tuning and stabilizing these exponents. We propose 2SED Fractional-Order Stochastic Gradient Descent (2SEDFOSGD), which integrates the Two-Scale Effective Dimension (2SED) algorithm with FOSGD to adapt the fractional exponent in a data-driven manner. By tracking model sensitivity and effective dimensionality, 2SEDFOSGD dynamically modulates the exponent to mitigate oscillations and hasten convergence. Theoretically, for onoconvex optimization problems, this approach preserves the advantages of fractional memory without the sluggish or unstable behavior observed in naïve fractional SGD. Empirical evaluations in Gaussian and α-stable noise scenarios using an autoregressive (AR) model highlight faster convergence and more robust parameter estimates compared to baseline methods, underscoring the potential of dimension-aware fractional techniques for advanced modeling and estimation tasks. © 2025, CC BY.

关键词： Convex optimization

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Mechanical Characterization of Biostable Dental Restoratives and Adhesives

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Dental Materials 2025年 41卷 e36-e36页

作者： Gouveia, Z Finer, Y Santerre, P Faculty of Dentistry University of Toronto Toronto Canada Institute of Biomedical Engineering University of Toronto Toronto Canada Translational Biology and Engineering Program University of Toronto Toronto Canada Department of Chemical Engineering and Applied Chemistry University of Toronto Toronto Canada

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Axisymmetric and azimuthal waves on a vibrated sessile drop

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Physical Review Fluids 2023年第11期8卷 110510-110510页

作者： D. Panda L. Kahouadji L. S. Tuckerman S. Shin J. Chergui D. Juric O. K. Matar Department of Chemical Engineering Imperial College London London SW7 2AZ United Kingdom Physique et Mécanique des Milieux Hétérogènes CNRS ESPCI Paris Université PSL Sorbonne Université Université de Paris 75005 Paris France Department of Mechanical and System Design Engineering Hongik University Seoul 04066 Republic of Korea Université Paris Saclay Centre National de la Recherche Scientifique (CNRS) Laboratoire Interdisciplinaire des Sciences du Numérique (LISN) 91400 Orsay France Department of Applied Mathematics and Theoretical Physics University of Cambridge Cambridge CB3 0WA United Kingdom

This paper is associated with a poster winner of a 2022 American Physical Society's Division of Fluid Dynamics (DFD) Gallery of Fluid Motion Award for work presented at the DFD Gallery of Fluid Motion. The origina... 详细信息

关键词： Capillary waves Contact line dynamics Drop & bubble phenomena Drops & bubbles Faraday waves Flow instability Interfacial flows Multiphase flows Pattern formation

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