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arXiv 2024年

作者： Rajagopala, Abhi D. Hashim, Akel Fruitwala, Neelay Huang, Gang Xu, Yilun Hines, Jordan Siddiqi, Irfan Klymko, Katherine Nowrouzi, Kasra Applied Math and Computational Research Division Lawrence Berkeley National Lab BerkeleyCA94720 United States Quantum Nanoelectronics Laboratory Department of Physics University of California at Berkeley BerkeleyCA94720 United States Accelerator Technology and Applied Physics Division Lawrence Berkeley National Lab BerkeleyCA94720 United States Department of Physics University of California at Berkeley BerkeleyCA94720 United States Materials Sciences Division Lawrence Berkeley National Lab BerkeleyCA94720 United States National Energy Research Scientific Computing Center Lawrence Berkeley National Lab BerkeleyCA94720 United States

Standard compilers for quantum circuits decompose arbitrary single-qubit gates into a sequence of physical Xπ/2 pulses and virtual-Z phase gates. Consequently, many circuit classes implement different logic operations but have an equivalent structure of physical pulses that only differ by changes in virtual phases. When many structurally-equivalent circuits need to be measured, generating sequences for each circuit is unnecessary and cumbersome, since compiling and loading sequences onto classical control hardware is a primary bottleneck in quantum circuit execution. In this work, we develop a hardware-assisted protocol for executing parameterized circuits on our FPGA-based control hardware, QubiC. This protocol relies on a hardware-software co-design technique in which software identifies structural equivalency in circuits and "peels" off the relevant parameterized angles to reduce the overall waveform compilation time. The hardware architecture then performs real-time "stitching" of the parameters in the circuit to measure circuits that implement a different overall logical operation. This work demonstrates significant speed ups in the total execution time for several different classes of quantum circuits. Copyright © 2024, The Authors. All rights reserved.

关键词： Quantum computers

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Defining eccentricity for gravitational wave astronomy

arXiv

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arXiv 2023年

作者： Shaikh, Md Arif Varma, Vijay Pfeiffer, Harald P. Ramos-Buades, Antoni van de Meent, Maarten Department of Physics and Astronomy Seoul National University Seoul08826 Korea Republic of International Centre for Theoretical Sciences Tata Institute of Fundamental Research Bangalore560089 India PotsdamD-14476 Germany Department of Mathematics Center for Scientific Computing and Data Science Research University of Massachusetts DartmouthMA02747 United States Niels Bohr International Academy Niels Bohr Institute Blegdamsvej 17 Copenhagen2100 Denmark

Eccentric compact binary mergers are significant scientific targets for current and future gravitational wave observatories. To detect and analyze eccentric signals, there is an increasing effort to develop waveform models, numerical relativity simulations, and parameter estimation frameworks for eccentric binaries. Unfortunately, current models and simulations use different internal parameterisations of eccentricity in the absence of a unique natural definition of eccentricity in general relativity, which can result in incompatible eccentricity measurements. In this paper, we adopt a standardized definition of eccentricity and mean anomaly based solely on waveform quantities, and make our implementation publicly available through an easy-to-use Python package, gw_eccentricity. This definition is free of gauge ambiguities, has the correct Newtonian limit, and can be applied as a postprocessing step when comparing eccentricity measurements from different models. This standardization puts all models and simulations on the same footing and enables direct comparisons between eccentricity estimates from gravitational wave observations and astrophysical predictions. We demonstrate the applicability of this definition and the robustness of our implementation for waveforms of different origins, including post-Newtonian theory, effective one body, extreme mass ratio inspirals, and numerical relativity simulations. We focus on binaries without spin-precession in this work, but possible generalizations to spin-precessing binaries are discussed. © 2023, CC BY.

关键词： Gravity waves

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Applying higher-modes consistency test on GW190814 : lessons on no-hair theorem, nature of the secondary compact object and waveform modeling

arXiv

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arXiv 2021年

作者： Islam, Tousif Center for Scientific Computing and Visualization Research University of Massachusetts DartmouthMA02747 United States Department of Physics University of Massachusetts DartmouthMA02747 United States Department of Mathematics University of Massachusetts DartmouthMA02747 United States Kavli Institute for Theoretical Physics University of California Santa BarbaraCA93106 United States

As one of the consequences of the black-hole "no-hair" theorem in general relativity (GR), the multipolar structure of the radiation (i.e. different spherical harmonic modes) from a merging quasi-circular binary black hole (BBH) is fully determined by the intrinsic parameters (i.e. the masses and spins of the companion black holes). In Refs. [1, 2], we have formulated an efficient test named ‘higher-modes consistency test’ to check for the consistency of the observed gravitational-wave (GW) signal with the expected multipolar structure of radiation from BBHs in GR. Detection of the high-mass-ratio merger of GW190814 enables the observation of spherical harmonic modes beyond the dominant (`, m) = (2, ±2) mode;thereby providing a unique opportunity to perform the ‘higher-modes consistency test’. Using different state-of-art waveform models (IMRPhenomXPHM, IMRPhenomXHM, IMRPhenomHM and SEONNRv4HM ROM), we show that GW190814 strongly favors the "no-hair" hypothesis in GR over a hypothesis that assumes generic deviation from the multipolar structure of the radiation by a Bayes factor of logeB ∼ 8. We further investigate any potential systematic errors arising as a result of different waveform modeling choices as well as due to neglecting many higher order modes. We find that, if the waveform model includes only (`, m) = (3, ±3) mode in its higher harmonics, the same event may reject the ‘no-hair’ hypothesis in GR when the detector sensitivity improves by a factor of 12.5. Our analysis, therefore, provides motivation to include as many higher order modes as possible in future waveform models. Copyright © 2021, The Authors. All rights reserved.

关键词： Merging

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Exploring End-to-end Differentiable Neural Charged Particle Tracking – A Loss Landscape Perspective

arXiv

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arXiv 2024年

作者： Kortus, Tobias Keidel, Ralf Gauger, Nicolas R. Aehle, Max Alme, Johan Barnaföldi, Gergely Gábor Bodova, Tea Borshchov, Vyacheslav van den Brink, Anthony Chaar, Mamdouh Eikeland, Viljar Feofilov, Gregory Garth, Christoph Gauger, Nicolas R. Genov, Georgi Grøttvik, Ola Helstrup, Håvard Igolkin, Sergey Keidel, Ralf Kobdaj, Chinorat Kortus, Tobias Leonhardt, Viktor Mehendale, Shruti Mulawade, Raju Ningappa Odland, Odd Harald O’Neill, George Papp, Gábor Peitzmann, Thomas Pettersen, Helge Egil Seime Piersimoni, Pierluigi Protsenko, Maksym Rauch, Max Rehman, Attiq Ur Richter, Matthias Röhrich, Dieter Santana, Joshua Schilling, Alexander Seco, Joao Songmoolnak, Arnon Sudár, Ákos Sølie, Jarle Rambo Tambave, Ganesh Tymchuk, Ihor Ullaland, Kjetil Varga-Kofarago, Monika Wagner, Boris Xiao, RenZheng Yang, Shiming Yokoyama, Hiroki Germany TU Kaiserslautern Kaiserslautern67663 Germany Department of Physics and Technology University of Bergen Bergen5007 Norway Wigner Research Centre for Physics Budapest Hungary Research and Production Enterprise"LTU" [RPELTU Kharkiv Ukraine Institute for Subatomic Physics Utrecht University/Nikhef Utrecht Netherlands St. Petersburg University St. Petersburg Russia Scientific Visualization Lab TU Kaiserslautern Kaiserslautern67663 Germany Department of Computer Science Electrical Engineering and Mathematical Sciences Western Norway University of Applied Sciences Bergen5020 Norway Center for Technology and Transfer [ZTT University of Applied Sciences Worms Worms Germany Institute of Science Suranaree University of Technology Nakhon Ratchasima Thailand Department of Oncology and Medical Physics Haukeland University Hospital Bergen5021 Norway Institute for Physics Eötvös Loránd University 1/A Pázmány P. Sétány BudapestH-1117 Hungary UniCamillus – Saint Camillus International University of Health Sciences Rome Italy Department of Physics University of Oslo Oslo0371 Norway Department of Biomedical Physics in Radiation Oncology DKFZ—German Cancer Research Center Heidelberg Germany Department of Physics and Astronomy Heidelberg University Heidelberg Germany Budapest University of Technology and Economics Budapest Hungary Department of Diagnostic Physics Division of Radiology and Nuclear Medicine Oslo University Hospital Oslo Norway Center for Medical and Radiation Physics [CMRP National Institute of Science Education and Research [NISER Bhubaneswar India College of Mechanical & Power Engineering China Three Gorges University Yichang China

Measurement and analysis of high energetic particles for scientific, medical or industrial applications is a complex procedure, requiring the design of sophisticated detector and data processing systems. The development of adaptive and differentiable software pipelines using a combination of conventional and machine learning algorithms is therefore getting ever more important to optimize and operate the system efficiently while maintaining end-to-end (E2E) differentiability. We propose for the application of charged particle tracking an E2E differentiable decision-focused learning scheme using graph neural networks with combinatorial components solving a linear assignment problem for each detector layer. We demonstrate empirically that including differentiable variations of discrete assignment operations allows for efficient network optimization, working better or on par with approaches that lack E2E differentiability. In additional studies, we dive deeper into the optimization process and provide further insights from a loss landscape perspective. We demonstrate that while both methods converge into similar performing, globally well-connected regions, they suffer under substantial predictive instability across initialization and optimization methods, which can have unpredictable consequences on the performance of downstream tasks such as image reconstruction. We also point out a dependency between the interpolation factor of the gradient estimator and the prediction stability of the model, suggesting the choice of sufficiently small values. Given the strong global connectivity of learned solutions and the excellent training performance, we argue that E2E differentiability provides, besides the general availability of gradient information, an important tool for robust particle tracking to mitigate prediction instabilities by favoring solutions that perform well on downstream tasks. Copyright © 2024, The Authors. All rights reserved.

关键词： Charged particles

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Factorized Parameter Estimation for Real-Time Gravitational Wave Inference

arXiv

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arXiv 2022年

作者： Islam, Tousif Roulet, Javier Venumadhav, Tejaswi Center for Scientific Computing and Visualization Research University of Massachusetts DartmouthMA02747 United States Department of Mathematics University of Massachusetts DartmouthMA02747 United States Department of Physics University of Massachusetts DartmouthMA02747 United States Kavli Institute for Theoretical Physics University of California at Santa Barbara Santa BarbaraCA93106 United States TAPIR Walter Burke Institute for Theoretical Physics California Institute of Technology PasadenaCA91125 United States Department of Physics University of California at Santa Barbara Santa BarbaraCA93106 United States International Centre for Theoretical Sciences Tata Institute of Fundamental Research Bangalore560089 India

We present a parameter estimation framework for gravitational wave (GW) signals that brings together several ideas to accelerate the inference process. First, we use the relative binning algorithm to evaluate the signal-to-noise-ratio timeseries in each detector for a given choice of intrinsic parameters. Second, we decouple the estimation of the intrinsic parameters (such as masses and spins of the components) from that of the extrinsic parameters (such as distance, orientation, and sky location) that describe a binary compact object coalescence. We achieve this by semi-analytically marginalizing the posterior distribution over extrinsic parameters without repeatedly evaluating the waveform for a fixed set of intrinsic parameters. Finally, we augment samples of intrinsic parameters with extrinsic parameters drawn from their appropriate conditional distributions. We implement the method for binaries with aligned spins, restricted to the quadrupole mode of the signal. Using simulated GW signals, we demonstrate that the method produces full eleven-dimensional posteriors that match those from standard Bayesian inference. Our framework takes only ∼ 200 s to analyze a typical binary-black-hole signal and ∼ 250 s to analyze a typical binary-neutron-star signal using one computing core. Such real-time and accurate estimation of the binary source properties will greatly aid the interpretation of triggers from gravitational wave searches, as well as the search for possible electromagnetic counterparts. We make the framework publicly available via the GW inference package cogwheel. Copyright © 2022, The Authors. All rights reserved.

关键词： Gravity waves

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Spinor GW/Bethe-Salpeter calculations in BerkeleyGW: Implementation, symmetries, benchmarking, and performance

引用

Physical Review B 2022年第11期106卷 115127-115127页

作者： Bradford A. Barker Jack Deslippe Johannes Lischner Manish Jain Oleg V. Yazyev David A. Strubbe Steven G. Louie Department of Physics University of California Berkeley Berkeley California 94720 USA Materials Sciences Division Lawrence Berkeley National Laboratory Berkeley California 94720 USA Department of Physics University of California Merced Merced California 95343 USA National Energy Research Scientific Computing Center Lawrence Berkeley National Laboratory Berkeley California 94720 USA Department of Materials and Physics and Thomas Young Centre for Theory and Simulation of Materials Imperial College London London SW7 2AZ United Kingdom Center for Condensed Matter Theory Department of Physics Indian Institute of Science Bangalore 560012 India Institute of Physics Ecole Polytechnique Federale de Lausanne (EPFL) CH-1015 Lausanne Switzerland

computing the GW quasiparticle band structure and Bethe-Salpeter equation (BSE) absorption spectra for materials with spin-orbit coupling have commonly been done by treating GW corrections and spin-orbit coupling (SOC) as separate perturbations to density-functional theory. However, accurate treatment of materials with strong spin-orbit coupling (such as many topological materials of recent interest, and thermoelectrics) often requires a nonperturbative approach using spinor wave functions in the Kohn-Sham equation and GW/BSE. Such calculations have only recently become available, in particular for the BSE. We have implemented this approach in the plane-wave pseudopotential GW/BSE code BerkeleyGW, which is highly parallelized and widely used in the electronic-structure community. We present reference results for quasiparticle band structures and optical absorption spectra of solids with different strengths of spin-orbit coupling, including Si, Ge, GaAs, GaSb, CdSe, Au, and Bi2Se3. The calculated quasiparticle band gaps of these systems are found to agree with experiment to within a few tens of meV. SOC splittings are found to be generally in better agreement with experiment, including quasiparticle corrections to band energies. The absorption spectrum of GaAs is not significantly impacted by the inclusion of spin-orbit coupling due to its relatively small value (0.2 eV) in the Λ direction, while the absorption spectrum of GaSb calculated with the spinor GW/BSE captures the large spin-orbit splitting of peaks in the spectrum. For the prototypical topological insulator Bi2Se3, we find a drastic change in the low-energy band structure compared to that of DFT, with the spinorial treatment of the GW approximation correctly capturing the parabolic nature of the valence and conduction bands after including off-diagonal self-energy matrix elements. We present the detailed methodology, approach to spatial symmetries for spinors, comparison against other codes, and performanc

关键词： Electronic structure Quasiparticles & collective excitations Spin-orbit coupling GW method

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Gravitational tuning forks and hierarchical triple systems

arXiv

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arXiv 2021年

作者： Cardoso, Vitor Duque, Francisco Khanna, Gaurav CENTRA Departamento de Física Instituto Superior Técnico – IST Universidade de Lisboa – UL Avenida Rovisco Pais 1 Lisboa1049 Portugal Department of Physics Center for Scientific Computing and Visualization Research University of Massachusetts DarthmouthMA02747 United States Department of Physics University of Rhode Island KingstonRI02881 United States

We study gravitational wave (GW) emission in the strong-field regime by a hierarchical triple system composed of a binary system placed in the vicinity of a supermassive black hole (SMBH). The LIGO-Virgo collaboration recently reported evidence for coalescences with this dynamical origin. These systems are common in galactic centers and thus are a target for the space-based LISA mission as well as other advanced detectors. Doppler shifts, aberration, lensing and strong amplitude modulations are features present in the GW signal from these systems, built into our framework and with no need for phenomenological patches. We find that the binary can resonantly excite the quasinormal modes of the SMBH, as in the resonant excitation of two tuning forks with matching frequencies. The flux of energy crossing the SMBH horizon can be significant, when compared with that from standard extreme-mass-ratio inspirals. Therefore, these triple systems are excellent probes of strong-field physics and of the BH nature of compact objects. © 2021, CC BY.

关键词： Hierarchical systems

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Numerical relativity surrogate model with memory effects and post-Newtonian hybridization

arXiv

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arXiv 2023年

作者： Yoo, Jooheon Mitman, Keefe Varma, Vijay Boyle, Michael Field, Scott E. Deppe, Nils Hébert, François Kidder, Lawrence E. Moxon, Jordan Pfeiffer, Harald P. Scheel, Mark A. Stein, Leo C. Teukolsky, Saul A. Throwe, William Vu, Nils L. Cornell Center for Astrophysics and Planetary Science Cornell University IthacaNY14853 United States Theoretical Astrophysics 350-17 California Institute of Technology PasadenaCA91125 United States Am Mühlenberg 1 PotsdamD-14476 Germany Department of Mathematics Center for Scientific Computing and Data Science Research University of Massachusetts DartmouthMA02747 United States Department of Physics and Astronomy University of Mississippi UniversityMS38677 United States

Numerical relativity simulations provide the most precise templates for the gravitational waves produced by binary black hole mergers. However, many of these simulations use an incomplete waveform extraction technique—extrapolation—that fails to capture important physics, such as gravitational memory effects. Cauchy-characteristic evolution (CCE), by contrast, is a much more physically accurate extraction procedure that fully evolves Einstein’s equations to future null infinity and accurately captures the expected physics. In this work, we present a new surrogate model, NRHybSur3dq8_CCE, built from CCE waveforms that have been mapped to the post-Newtonian (PN) BMS frame and then hybridized with PN and effective one-body (EOB) waveforms. This model is trained on 102 waveforms with mass ratios q ≤ 8 and aligned spins χ1z, χ2z ∈ [−0.8,0.8]. The model spans the entire LIGO-Virgo-KAGRA (LVK) frequency band (with flow = 20Hz) for total masses M 2.25M☉ and includes the ≤ 4 and (,m) = (5,5) spin-weight −2 spherical harmonic modes, but not the (3,1), (4,2) or (4,1) modes. We find that NRHybSur3dq8_CCE can accurately reproduce the training waveforms with mismatches 2×10−4 for total masses 2.25M☉ ≤ M ≤ 300M☉ and can, for a modest degree of extrapolation, capably model outside of its training region. Most importantly, unlike previous waveform models, the new surrogate model successfully captures memory effects. Copyright © 2023, The Authors. All rights reserved.

关键词： Extrapolation

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Fast And Automatic Floating Point Error Analysis With CHEF-FP

arXiv

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arXiv 2023年

作者： Singh, Garima Kundu, Baidyanath Menon, Harshitha Penev, Alexander Lange, David J. Vassilev, Vassil European Council for Nuclear Research Espl. des Particules 1 Meyrin1211 Switzerland Department of Physics Princeton University PrincetonNJ08544 United States Center for Applied Scientific Computing Lawrence Livermore National Laboratory LivermoreCA94551 United States Faculty of Mathematics and Informatics University of Plovdiv 236 Bulgaria Blvd. Plovdiv4000 Bulgaria

As we reach the limit of Moore's Law, researchers are exploring different paradigms to achieve unprecedented performance. Approximate computing (AC), which relies on the ability of applications to tolerate some error in the results to trade-off accuracy for performance, has shown significant promise. Despite the success of AC in domains such as Machine Learning, its acceptance in High-Performance computing (HPC) is limited due to its stringent requirement of accuracy. We need tools and techniques to identify regions of the code that are amenable to approximations and their impact on the application output quality so as to guide developers to employ selective approximation. To this end, we propose CHEF-FP, a flexible, scalable, and easy-to-use source-code transformation tool based on Automatic Differentiation (AD) for analysing approximation errors in HPC applications. CHEF-FP uses Clad, an efficient AD tool built as a plugin to the Clang compiler and based on the LLVM compiler infrastructure, as a backend and utilizes its AD abilities to evaluate approximation errors in C++ code. CHEF-FP works at the source level by injecting error estimation code into the generated adjoints. This enables the error-estimation code to undergo compiler optimizations resulting in improved analysis time and reduced memory usage. We also provide theoretical and architectural augmentations to source code transformation-based AD tools to perform FP error analysis. In this paper, we primarily focus on analyzing errors introduced by mixed-precision AC techniques, the most popular approximate technique in HPC. We also show the applicability of our tool in estimating other kinds of errors by evaluating our tool on codes that use approximate functions. Moreover, we demonstrate the speedups achieved by CHEF-FP during analysis time as compared to the existing state-of-the-art tool as a result of its ability to generate and insert approximation error estimate code directly into the derivative sour

关键词： Error analysis

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Detection of anomalies amongst LIGO’s glitch populations with autoencoders

arXiv

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arXiv 2023年

作者： Laguarta, Paloma van der Laag, Robin Lopez, Melissa Dooney, Tom Miller, Andrew L. Schmidt, Stefano Cavaglia, Marco Caudill, Sarah Driessens, Kurt Karel, Joël Lenders, Roy Van Den Broeck, Chris Department of Advanced Computing Sciences Maastricht University Maastricht Netherlands Utrecht University Princetonplein 1 Utrecht3584 CC Netherlands Nikhef Science Park 105 Amsterdam1098 XG Netherlands Centre of Actionable Research Open University Heerlen Netherlands Physics Department Missouri University of Science and Technology 1315 N. Pine St. RollaMO65409 United States Department of Physics University of Massachusetts DartmouthMA02747 United States Center for Scientific Computing and Data Science Research University of Massachusetts DartmouthMA02747 United States Boosting Alpha B.V. Villafloraweg 1 SZ Venlo5928 Netherlands

Gravitational-wave (GW) interferometers are able to detect a change in distance of ∼ 1/10,000th the size of a proton. Such sensitivity leads to large appearance rates of non-Gaussian transient noise bursts in the main detector strain, also known as glitches. These glitches come in a wide range of frequency-amplitude-time morphologies and are caused by environmental or instrumental processes, hindering searches for all sources of gravitational waves. Current approaches for their identification use supervised models to learn their morphology in the main strain, but do not consider relevant information provided by auxiliary channels that monitor the state of the interferometers nor provide a flexible framework for novel glitch morphologies. In this work, we present an unsupervised algorithm to find anomalous glitches. We encode a subset of auxiliary channels from LIGO Livingston in the fractal dimension, a measure for the complexity of the data, and learn the underlying distribution of the data using an auto-encoder with periodic convolutions. In this way, we uncover unknown glitch morphologies, and overlaps in time between different glitches and misclassifications. This led to the discovery of anomalies in 6.6% of the input data. The results of this investigation stress the learnable structure of auxiliary channels encoded in fractal dimension and provide a flexible framework to improve the state-of-the-art of glitch identification algorithms. Copyright © 2023, The Authors. All rights reserved.

关键词： Fractal dimension

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