Article
Quantum Science & Technology
Maria Prat Colomer, Luke Mortimer, Irenee Frerot, Mate Farkas, Antonio Acin
Summary: This study numerically investigates Zauner's conjecture and finds that there are no four mutually unbiased bases in dimension six, while there are at most three MUBs in dimension ten.
Article
Multidisciplinary Sciences
Takahiro Yabe, P. Suresh C. Rao, Satish Ukkusuri, Susan L. Cutter
Summary: With rapid urbanization and increasing climate risks, it is crucial to enhance the resilience of urban systems. However, current studies on disaster resilience often rely on static measures and fail to incorporate the dynamic nature of resilience. This article argues for the use of big data and data-driven complex systems models to quantitatively simulate the recovery trajectories and intrinsic resilience characteristics of communities, paving the way for better policy applications.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Mathematics, Interdisciplinary Applications
Junfeng Lu, Yi Sun
Summary: This paper presents two numerical approaches for finding the approximated solutions of the time fractional Boussinesq-Burgers equations with He's fractional derivative. The FCT-HPM and HPTM solutions are provided without any linearization or complicated computation, and numerical comparisons illustrate the efficiency of these methods.
FRACTALS-COMPLEX GEOMETRY PATTERNS AND SCALING IN NATURE AND SOCIETY
(2021)
Article
Optics
Pejman Jouzdani, Calvin W. Johnson, Eduardo R. Mucciolo, Ionel Stetcu
Summary: This study proposes an alternative approach to implement imaginary time evolution (ITE) by using an orthogonal basis set to efficiently represent propagated states. The number of basis states needed can be controlled by precision and time increment, making the algorithm polynomial in the number of qubits. The algorithm is useful for studying nonlocal systems.
Article
Physics, Condensed Matter
John McFarland, Efstratios Manousakis
Summary: Imaginary-time time-dependent density functional theory (it-TDDFT) is proposed as an alternative method for obtaining the ground state within density functional theory, avoiding convergence difficulties encountered by the self-consistent-field iterative method. By modifying the Quantum ESPRESSO package, it-TDDFT propagation for periodic systems has been successfully implemented, demonstrating accurate results for different calculations using ultra-soft or norm-conserving pseudo potentials.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2021)
Article
Mathematics, Interdisciplinary Applications
N. H. Sweilam, S. M. AL-Mekhlafi, D. G. Mohamed
Summary: This paper numerically studies the behavior of two novel classes of fractional order chaotic systems, with fractal-fractional derivatives defined in the Caputo and Riemann-Liouville senses. Two Grunwald-Letnikov nonstandard finite difference schemes are presented for studying these systems, and the stability analysis of the methods is proved. Numerical simulations and comparative studies are used to demonstrate the simplicity and effectiveness of the proposed methods.
CHAOS SOLITONS & FRACTALS
(2021)
Article
Physics, Mathematical
Juerg Froehlich, Alessandro Pizzo
Summary: It is argued that the Schrodinger equation may not accurately describe the quantum-mechanical time evolution of isolated physical systems. A general statistical law within the ETH-Approach to Quantum Mechanics is proposed as a replacement for the unitary Schrodinger evolution, which resolves the measurement problem. Analysis of simple models involving heavy atoms coupled with quantized radiation fields illustrates the concepts and results. These models can be explicitly treated when the speed of light approaches infinity.
COMMUNICATIONS IN MATHEMATICAL PHYSICS
(2022)
Article
Quantum Science & Technology
Rizwanul Alam, George Siopsis, Rebekah Herrman, James Ostrowski, Phillip C. Lotshaw, Travis S. Humble
Summary: We propose an efficient method for solving the MaxCut problem using quantum imaginary time evolution (QITE). By utilizing a linear Ansatz for unitary updates and an initial state with no entanglement, along with an imaginary-time-dependent Hamiltonian, we achieve high-performance convergence to the maximum solution for the MaxCut problem in various randomly selected graphs. Our algorithm outperforms classical algorithms, such as the greedy and Goemans-Williamson algorithms, and we introduce the overlap of the QITE algorithm's final state with the ground state as a unique performance metric, highlighting its quantum advantage.
QUANTUM INFORMATION PROCESSING
(2023)
Article
Automation & Control Systems
Sen Kuang, Xiaoke Guan, Daoyi Dong
Summary: This paper investigates the finite-time control problem of quantum systems, defines finite-time stability, and presents a stability criterion and control law for particular quantum systems. The effectiveness of the proposed control scheme is demonstrated through numerical results.
Article
Mathematics, Applied
Enyu Fan, Changpin Li, Zhiqiang Li
Summary: This paper proposes three numerical formulas for approximating the Caputo-Hadamard fractional derivatives, which are applicable to different order ranges and exhibit high convergence. These formulas have been successfully applied to long-term integration of fractional differential systems after being verified.
COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION
(2022)
Article
Materials Science, Multidisciplinary
Tomas Lothman, Christopher Triola, Jorge Cayao, Annica M. Black-Schaffer
Summary: The EPOCH method is an efficient computational method for calculating time-dependent equilibrium Green's functions in large inhomogeneous systems. It generalizes from quantum chemistry methods and incorporates Fermi-Dirac statistics, with computational cost scaling linearly with system degrees of freedom.
Review
Physics, Multidisciplinary
John Rundle, Seth Stein, Andrea Donnellan, Donald L. Turcotte, William Klein, Cameron Saylor
Summary: Charles Richter's quote highlights the challenges in predicting earthquakes, despite efforts over a century. Two main approaches have been used: long-term forecasting based on fault motion and past seismic activity, and identifying precursors to earthquakes. While progress has been made with new data and technology, deterministic earthquake prediction remains uncertain.
REPORTS ON PROGRESS IN PHYSICS
(2021)
Review
Chemistry, Multidisciplinary
Jiajun Ren, Weitang Li, Tong Jiang, Yuanheng Wang, Zhigang Shuai
Summary: Simulations of spectroscopy and quantum dynamics are crucial for understanding electronic processes in complex systems. Time-dependent density matrix renormalization group (TD-DMRG) is an accurate and efficient method for high-dimensional full-quantum dynamics, capable of handling mixed state density matrices and enabling quantum statistical description.
WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
S. Yamamoto, R. Kaji, S. Adachi
Summary: In this study, the formation of the anomalous Hanle effect in a self-assembled quantum dot was investigated using experimental and theoretical approaches. The buildup time of the nuclear field was found to increase with increasing applied transverse magnetic field strength. Additionally, the inversion of the circular polarization degree of photoluminescence was observed to occur much faster than the buildup time of the nuclear field, indicating the importance of the in-plane component of the major principal axis of nuclear quadrupole interaction.
Article
Automation & Control Systems
Kerianne L. Hobbs, Mark L. Mote, Matthew C. L. Abate, Samuel D. Coogan, Eric M. Feron
Summary: This article introduces the concepts of runtime assurance (RTA) and its role in ensuring the safety of complex control systems. Assuming the readers have an undergraduate-level understanding of control theory and state-space concepts, the article provides theory and examples for RTA architectures, four types of RTA approaches, and considerations for employing RTA in safety-critical cyberphysical systems.
IEEE CONTROL SYSTEMS MAGAZINE
(2023)
Article
Computer Science, Hardware & Architecture
Faisal Shahzad, Moritz Kreutzer, Thomas Zeiser, Rui Machado, Andreas Pieper, Georg Hager, Gerhard Wellein
INTERNATIONAL JOURNAL OF HIGH PERFORMANCE COMPUTING APPLICATIONS
(2018)
Article
Mathematics, Applied
Andreas Alvermann, Achim Basermann, Hans-Joachim Bungartz, Christian Carbogno, Dominik Ernst, Holger Fehske, Yasunori Futamura, Martin Galgon, Georg Hager, Sarah Huber, Thomas Huckle, Akihiro Ida, Akira Imakura, Masatoshi Kawai, Simone Koecher, Moritz Kreutzer, Pavel Kus, Bruno Lang, Hermann Lederer, Valeriy Manin, Andreas Marek, Kengo Nakajima, Lydia Nemec, Karsten Reuter, Michael Rippl, Melven Roehrig-Zoellner, Tetsuya Sakurai, Matthias Scheffler, Christoph Scheurer, Faisal Shahzad, Danilo Simoes Brambila, Jonas Thies, Gerhard Wellein
JAPAN JOURNAL OF INDUSTRIAL AND APPLIED MATHEMATICS
(2019)
Article
Computer Science, Hardware & Architecture
Francesco Cremonesi, Georg Hager, Gerhard Wellein, Felix Schuermann
INTERNATIONAL JOURNAL OF HIGH PERFORMANCE COMPUTING APPLICATIONS
(2020)
Article
Computer Science, Software Engineering
Jonas Thies, Melven Roehrig-Zoellner, Nigel Overmars, Achim Basermann, Dominik Ernst, Georg Hager, Gerhard Wellein
ACM TRANSACTIONS ON MATHEMATICAL SOFTWARE
(2020)
Article
Computer Science, Hardware & Architecture
Axel Klawonn, Martin Lanser, Oliver Rheinbach, Gerhard Wellein, Markus Wittmann
Summary: The nonlinear domain decomposition method improves energy efficiency by utilizing asynchronicity and allows for significant energy savings compared to traditional methods. It does not impact the total solution time and can reduce energy consumption significantly.
INTERNATIONAL JOURNAL OF HIGH PERFORMANCE COMPUTING APPLICATIONS
(2021)
Article
Computer Science, Hardware & Architecture
Dominik Ernst, Georg Hager, Jonas Thies, Gerhard Wellein
Summary: The study discusses the challenges and key characteristics of implementing general matrix-matrix multiplications with double-precision real and complex entries in vendor-supplied BLAS libraries. It evaluates different strategies of parallelization and thread distribution and devises a flexible, configurable mapping scheme. By using code generation combined with autotuning, the implementation achieves at least 2/3 of the roofline performance for a large range of matrix sizes and often outperforms state-of-the art CUBLAS results on an NVIDIA Volta GPGPU.
INTERNATIONAL JOURNAL OF HIGH PERFORMANCE COMPUTING APPLICATIONS
(2021)
Article
Computer Science, Software Engineering
Christie Alappat, Nils Meyer, Jan Laukemann, Thomas Gruber, Georg Hager, Gerhard Wellein, Tilo Wettig
Summary: The A64FX CPU is the most powerful Arm-based processor design to date, with performance and memory bandwidth comparable to accelerator devices. Understanding its performance features is crucial for developers. This study analyzes the architecture of the A64FX and presents optimization strategies. A comparison with other high-end systems highlights the capabilities of the A64FX. Additionally, the potential for power optimization using the Fugaku system's tuning knobs is explored.
CONCURRENCY AND COMPUTATION-PRACTICE & EXPERIENCE
(2022)
Article
Computer Science, Software Engineering
Ayesha Afzal, Georg Hager, Gerhard Wellein
Summary: Complex applications running on multicore processors exhibit diverse performance phenomena. However, the increasing number of cores in ccNUMA domains complicates the analysis of memory-bound code performance. To address this issue, researchers have developed a performance model that can predict the memory bandwidth share per core in a memory contention domain.
CONCURRENCY AND COMPUTATION-PRACTICE & EXPERIENCE
(2022)
Article
Computer Science, Artificial Intelligence
Dimosthenis Pasadakis, Christie Louis Alappat, Olaf Schenk, Gerhard Wellein
Summary: The study introduces a novel direct multiway spectral clustering algorithm based on p-norm, using a nonlinear reformulation of the spectral clustering method to achieve improved numerical benefits within a certain range. By recasting the problem and promoting sparser solution vectors, it aims to achieve optimal graph cuts as p approaches one.
Proceedings Paper
Computer Science, Hardware & Architecture
Dominik Ernst, Georg Hager, Matthias Knorr, Gerhard Wellein, Markus Holzer
Summary: This paper addresses the selection problem by identifying relevant performance-defining mechanisms through a performance model coupled with an analytic hardware metric estimator. This enables a quick exploration of large configuration spaces to identify highly efficient candidates with high accuracy.
2021 IEEE 33RD INTERNATIONAL SYMPOSIUM ON COMPUTER ARCHITECTURE AND HIGH PERFORMANCE COMPUTING (SBAC-PAD 2021)
(2021)
Article
Materials Science, Multidisciplinary
Alexander Filusch, Alan R. Bishop, Avadh Saxena, Gerhard Wellein, Holger Fehske
Summary: This study investigates the valley-filtering capabilities of a quantum dot inscribed by locally straining an alpha-T-3 lattice. Different transport regimes are detected based on the width and width-to-height ratio of the quantum dot, with and without valley filtering. Analysis of conductance resonances with high valley polarization reveals insights into related Landau levels and local current densities. The observed local charge and current density patterns reflect the effects of strain-induced local inversion symmetry breaking and global inversion symmetry breaking due to the scaling parameter alpha.
Proceedings Paper
Computer Science, Theory & Methods
Martin Bauer, Johannes Hoetzer, Dominik Ernst, Julian Hammer, Marco Seiz, Henrik Hierl, Jan Hoenig, Harald Koestler, Gerhard Wellein, Britta Nestler, Ulrich Ruede
PROCEEDINGS OF SC19: THE INTERNATIONAL CONFERENCE FOR HIGH PERFORMANCE COMPUTING, NETWORKING, STORAGE AND ANALYSIS
(2019)
Proceedings Paper
Computer Science, Hardware & Architecture
Jan Eitzinger, Thomas Gruber, Ayesha Afzal, Thomas Zeiser, Gerhard Wellein
2019 IEEE INTERNATIONAL CONFERENCE ON CLUSTER COMPUTING (CLUSTER)
(2019)
Proceedings Paper
Computer Science, Theory & Methods
Moritz Kreutzer, Dominik Ernst, Alan R. Bishop, Holger Fehske, Georg Hager, Kengo Nakajima, Gerhard Wellein
HIGH PERFORMANCE COMPUTING, ISC HIGH PERFORMANCE 2018
(2018)
Article
Computer Science, Theory & Methods
Christie Alappat, Achim Basermann, Alan R. Bishop, Holger Fehske, Georg Hager, Olaf Schenk, Jonas Thies, Gerhard Wellein
ACM TRANSACTIONS ON PARALLEL COMPUTING
(2020)
Article
Physics, Multidisciplinary
Tinggui Chen, Baizhan Xia, Dejie Yu, Chuanxing Bi
Summary: This study proposes a gradient phononic crystal structure for enhanced acoustic sensing. By breaking the symmetry of the PC structure, topologically protected edge states are introduced, resulting in topological acoustic rainbow trapping. The robustness and enhancement properties are verified numerically and experimentally.
