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quantum speedup for track reconstruction in particle accelerators

Physical Review D 2022年第7期105卷 076012-076012页

作者： D. Magano A. Kumar M. Kālis A. Locāns A. Glos S. Pratapsi G. Quinta M. Dimitrijevs A. Rivošs P. Bargassa J. Seixas A. Ambainis Y. Omar Physics of Information and Quantum Technologies Group Instituto de Telecomunicações Av. Rovisco Pais 1 1049-001 Lisboa Portugal Instituto Superior Técnico Universidade de Lisboa Av. Rovisco Pais 1 1049-001 Lisboa Portugal Department of Mathematics Clarkson University Potsdam New York 13699 USA Center for Quantum Computer Science Faculty of Computing University of Latvia Raiņa bulv. 19 R𝚤ga LV-1586 Latvia Institute of Theoretical and Applied Informatics Polish Academy of Sciences Bałtycka 5 44-100 Gliwice Poland Portuguese Quantum Institute Av. Rovisco Pais 1 1049-001 Lisboa Portugal Laboratório de Instrumentação e Física Experimental de Partículas Av. Pr. Gama Pinto 2 1649-003 Lisbon Portugal Center for Physics and Engineering of Advanced Materials Av. Rovisco Pais 1 1049-001 Lisbon Portugal

To investigate the fundamental nature of matter and its interactions, particles are accelerated to very high energies and collided inside detectors, producing a multitude of other particles that are scattered in all directions. As charged particles traverse the detector, they leave signals of their passage. The problem of track reconstruction is to recover the original trajectories from these signals. This challenging data analysis task will become even more demanding as the luminosity of future accelerators increases, leading to collision events with a more complex structure. We identify four fundamental routines present in every local tracking method and analyze how they scale in the context of a standard tracking algorithm. We show that for some of these routines we can reach a lower computational complexity with quantum search algorithms. Although the found quantum speedups are mild, this constitutes, to the best of our knowledge, the first rigorous evidence of a quantum advantage for a high-energy physics data processing task.

关键词： quantum algorithms

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Yang-Lee edge singularity triggered entanglement transition

arXiv

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arXiv 2021年

作者： Jian, Shao-Kai Yang, Zhi-Cheng Bi, Zhen Chen, Xiao Condensed Matter Theory Center Department of Physics University of Maryland College ParkMD20742 United States Joint Quantum Institute University of Maryland College ParkMD20742 United States Joint Center for Quantum Information and Computer Science University of Maryland College ParkMD20742 United States Department of Physics The Pennsylvania State University University ParkPA16802 United States Department of Physics Boston College Chestnut HillMA02467 United States

We show that a class of PT symmetric non-Hermitian Hamiltonians realizing the Yang-Lee edge singularity exhibits an entanglement transition in the long-time steady state evolved under the Hamiltonian. Such a transition is induced by a level crossing triggered by the critical point associated with the Yang-Lee singularity and hence is first-order in nature. At the transition, the entanglement entropy of the steady state jumps discontinuously from a volume-law to an area-law scaling. We exemplify this mechanism using a one-dimensional transverse field Ising model with additional imaginary fields, as well as the spin-1 Blume-Capel model and the three-state Potts model. We further make a connection to the forced-measurement induced entanglement transition in a Floquet non-unitary circuit subject to continuous measurements followed by post-selections. Our results demonstrate a new mechanism for entanglement transitions in non-Hermitian systems harboring a critical point. Copyright © 2021, The Authors. All rights reserved.

关键词： Hamiltonians

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NASDUCK SERF: New constraints on axion-like dark matter from a SERF comagnetometer

arXiv

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arXiv 2022年

作者： Bloch, Itay M. Shaham, Roy Hochberg, Yonit Kuflik, Eric Volansky, Tomer Katz, Or Berkeley Center for Theoretical Physics University of California BerkeleyCA94720 United States Theory Group Lawrence Berkeley National Laboratory BerkeleyCA94720 United States Rafael Ltd. Haifa31021 Israel Department of Physics of Complex Systems Weizmann Institute of Science Rehovot76100 Israel Racah Institute of Physics Hebrew University of Jerusalem Jerusalem91904 Israel Department of Physics Tel Aviv University Tel Aviv Israel Duke Quantum Center Duke University DurhamNC27701 United States Department of Electrical and Computer Engineering Duke University DurhamNC27708 United States

Ultralight axion-like particles are well-motivated relics that might compose the cosmological dark matter and source anomalous time-dependent magnetic fields. We report on new terrestrial bounds on the coupling of axion-like particles to neutrons and protons. The detector uses nuclei of noble-gas and alkali-metal atoms and operates in the Spin-Exchange Relaxation-Free (SERF) regime, achieving high sensitivity to axion-like dark matter fields. Conducting a month-long search, we cover the mass range of 1.4 × 10−12 eV/c2 to 2 × 10−10 eV/c2 and provide world-leading limits which supersede robust astrophysical bounds, and improve upon previous terrestrial constraints by up to two orders of magnitudes for many masses within this range. These are the first reliable terrestrial bounds reported on the coupling of protons with axion-like dark matter, covering a new and unexplored terrain in its parameter space. © 2022, CC BY.

关键词： Dark Matter

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Persuasion and incentives through the lens of duality

arXiv

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arXiv 2019年

作者： Dughmi, Shaddin Niazadeh, Rad Psomas, Alexandros Weinberg, S. Matthew Department of Computer Science University of Southern California Department of Computer Science Stanford University Simons Institute for the Theory of Computing Department of Computer Science Princeton University

Lagrangian duality underlies both classical and modern mechanism design. In particular, the dual perspective often permits simple and detail-free characterizations of optimal and approximately optimal mechanisms. This paper applies this same methodology to a close cousin of traditional mechanism design, one which shares conceptual and technical elements with its more mature relative: the burgeoning field of persuasion. The dual perspective permits us to analyze optimal persuasion schemes both in settings which have been analyzed in prior work, as well as for natural generalizations which we are the first to explore in depth. Most notably, we permit combining persuasion policies with payments, which serve to augment the persuasion power of the scheme. In both single and multi-receiver settings, as well as under a variety of constraints on payments, we employ duality to obtain structural insights, as well as tractable and simple characterizations of optimal policies. Copyright © 2019, The Authors. All rights reserved.

关键词： Machine design

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Multiscale evolution of charmed particles in a nuclear medium

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Physical Review C 2023年第5期107卷 054901-054901页

作者： W. Fan G. Vujanovic S. A. Bass A. Majumder A. Angerami R. Arora S. Cao Y. Chen T. Dai L. Du R. Ehlers H. Elfner R. J. Fries C. Gale Y. He M. Heffernan U. Heinz B. V. Jacak P. M. Jacobs S. Jeon Y. Ji K. Kauder L. Kasper W. Ke M. Kelsey M. Kordell, II A. Kumar J. Latessa Y.-J. Lee D. Liyanage A. Lopez M. Luzum S. Mak A. Mankolli C. Martin H. Mehryar T. Mengel J. Mulligan C. Nattrass D. Oliinychenko J.-F. Paquet J. H. Putschke G. Roland B. Schenke L. Schwiebert A. Sengupta C. Shen A. Silva C. Sirimanna D. Soeder R. A. Soltz I. Soudi J. Staudenmaier M. Strickland Y. Tachibana J. Velkovska X.-N. Wang R. L. Wolpert W. Zhao Department of Physics Duke University Durham North Carolina 27708 USA Department of Physics and Astronomy Wayne State University Detroit Michigan 48201 USA Department of Physics University of Regina Regina SK S4S 0A2 Canada Lawrence Livermore National Laboratory Livermore California 94550 USA Research Computing Group University Technology Solutions The University of Texas at San Antonio San Antonio Texas 78249 USA Institute of Frontier and Interdisciplinary Science Shandong University Qingdao Shandong 266237 China Laboratory for Nuclear Science Massachusetts Institute of Technology Cambridge Massachusetts 02139 USA Department of Physics Massachusetts Institute of Technology Cambridge Massachusetts 02139 USA Department of Physics McGill University Montréal QC H3A 2T8 Canada Department of Physics and Astronomy University of Tennessee Knoxville Tennessee 37996 USA Physics Division Oak Ridge National Laboratory Oak Ridge Tennessee 37830 USA GSI Helmholtzzentrum für Schwerionenforschung 64291 Darmstadt Germany Institute for Theoretical Physics Goethe University 60438 Frankfurt am Main Germany Frankfurt Institute for Advanced Studies 60438 Frankfurt am Main Germany Cyclotron Institute Texas A&M University College Station Texas 77843 USA Department of Physics and Astronomy Texas A&M University College Station Texas 77843 USA Guangdong Provincial Key Laboratory of Nuclear Science Institute of Quantum Matter South China Normal University Guangzhou 510006 China Guangdong-Hong Kong Joint Laboratory of Quantum Matter Southern Nuclear Science Computing Center South China Normal University Guangzhou 510006 China Department of Physics The Ohio State University Columbus Ohio 43210 USA Department of Physics University of California Berkeley California 94270 USA Nuclear Science Division Lawrence Berkeley National Laboratory Berkeley California 94270 USA Department of Statistical Science Duke University Durham North Carolina 27708 USA Department of Phy

Parton energy-momentum exchange with the quark gluon plasma (QGP) is a multiscale problem. In this work, we calculate the interaction of charm quarks with the QGP within the higher twist formalism at high virtuality and high energy using the Modular All Twist Transverse-scattering Elastic-drag and Radiation (MATTER) model, while the low-virtuality and high-energy portion is treated via a linearized Boltzmann transport formalism. Coherence effect that reduces the medium-induced emission rate in the MATTER model is also taken into account through a virtuality-dependent q̂, leaving the simultaneous dependence of q̂ on heavy quark mass and virtuality for future studies. The interplay between these two formalisms is studied phenomenologically and used to produce a first description of the D-meson and charged hadron nuclear modification factor RAA across multiple centralities. All calculations were carried out utilizing the Jet Energy-loss Tomography with a Statistically and Computationally Advanced Program Envelope framework.

关键词： Jets & heavy flavor physics Relativistic heavy-ion collisions

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Hierarchy of Linear Light Cones with Long-Range Interactions

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Physical Review X 2020年第3期10卷 031009-031009页

作者： Minh C. Tran Chi-Fang Chen Adam Ehrenberg Andrew Y. Guo Abhinav Deshpande Yifan Hong Zhe-Xuan Gong Alexey V. Gorshkov Andrew Lucas Joint Center for Quantum Information and Computer Science NIST/University of Maryland College Park Maryland 20742 USA Joint Quantum Institute NIST/University of Maryland College Park Maryland 20742 USA Department of Physics California Institute of Technology Pasadena California 91125 USA Department of Physics University of Colorado Boulder Colorado 80309 USA Department of Physics Colorado School of Mines Golden Colorado 80401 USA National Institute of Standard and Technology Boulder Colorado 80305 USA Center for Theory of Quantum Matter University of Colorado Boulder Colorado 80309 USA

In quantum many-body systems with local interactions, quantum information and entanglement cannot spread outside of a linear light cone, which expands at an emergent velocity analogous to the speed of light. Local operations at sufficiently separated spacetime points approximately commute—given a many-body state |ψ⟩, Ox(t)Oy|ψ⟩≈OyOx(t)|ψ⟩ with arbitrarily small errors—so long as |x−y|≳vt, where v is finite. Yet, most nonrelativistic physical systems realized in nature have long-range interactions: Two degrees of freedom separated by a distance r interact with potential energy V(r)∝1/rα. In systems with long-range interactions, we rigorously establish a hierarchy of linear light cones: At the same α, some quantum information processing tasks are constrained by a linear light cone, while others are not. In one spatial dimension, this linear light cone exists for every many-body state |ψ⟩ when α>3 (Lieb-Robinson light cone); for a typical state |ψ⟩ chosen uniformly at random from the Hilbert space when α>52 (Frobenius light cone); and for every state of a noninteracting system when α>2 (free light cone). These bounds apply to time-dependent systems and are optimal up to subalgebraic improvements. Our theorems regarding the Lieb-Robinson and free light cones—and their tightness—also generalize to arbitrary dimensions. We discuss the implications of our bounds on the growth of connected correlators and of topological order, the clustering of correlations in gapped systems, and the digital simulation of systems with long-range interactions. In addition, we show that universal quantum state transfer, as well as many-body quantum chaos, is bounded by the Frobenius light cone and, therefore, is poorly constrained by all Lieb-Robinson bounds.

关键词： Boson sampling Mathematical physics quantum protocols quantum state transfer quantum walks

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Improved upper bounds for the hitting times of quantum walks

arXiv

引用

arXiv 2020年

作者： Atia, Yosi Chakraborty, Shantanav School of Computer Science and Engineering The Hebrew University Jerusalem Israel University of Texas AustinTX United States Centre for Quantum Science and Technology International Institute of Information Technology Telangana Hyderabad India Centre for Security Theory and Algorithmic Research International Institute of Information Technology Telangana Hyderabad India

Continuous-time quantum walks have proven to be an extremely useful framework for the design of several quantum algorithms. Often, the running time of quantum algorithms in this framework is characterized by the quantum hitting time: the time required by the quantum walk to find a vertex of interest with a high probability. In this article, we provide improved upper bounds for the quantum hitting time that can be applied to several CTQW-based quantum algorithms. In particular, we apply our techniques to the glued-trees problem, improving their hitting time upper bound by a polynomial factor: from O(n5) to O(n2 log n). Furthermore, our methods also help to exponentially improve the dependence on precision of the continuous-time quantum walk based algorithm to find a marked node on any ergodic, reversible Markov chain by Chakraborty et al. [PRA 102, 022227 (2020)]. Copyright © 2020, The Authors. All rights reserved.

关键词： quantum theory

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Entangled subspaces and generic local state discrimination with pre-shared entanglement

arXiv

引用

arXiv 2020年

作者： Lovitz, Benjamin Johnston, Nathaniel Institute for Quantum Computing Department of Applied Mathematics University of Waterloo 200 University Ave W WaterlooON Canada Department of Mathematics & Computer Science Mount Allison University Canada Department of Mathematics & Statistics University of Guelph Canada

Walgate and Scott have determined the maximum number of generic pure quantum states that can be unambiguously discriminated by an LOCC measurement [42]. In this work, we determine this number in a more general setting in which the local parties have access to pre-shared entanglement in the form of a resource state. We find that, for an arbitrary pure resource state, this number is equal to the Krull dimension of (the closure of) the set of pure states obtainable from the resource state by SLOCC. Surprisingly, a generic resource state maximizes this number. Local state discrimination is closely related to the topic of entangled subspaces, which we study in its own right. We introduce r-entangled subspaces, which naturally generalize previously studied spaces to higher multipartite entanglement. We use algebraic-geometric methods to determine the maximum dimension of an r-entangled subspace, and present novel explicit constructions of such spaces. We obtain similar results for symmetric and antisymmetric rentangled subspaces, which correspond to entangled subspaces of bosonic and fermionic systems, respectively. © 2020, CC BY.

关键词： Algebra

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Surface Code Design for Asymmetric Error Channels

arXiv

引用

arXiv 2021年

作者： Azad, Utkarsh Lipińska, Aleksandra Mahato, Shilpa Sachdeva, Rijul Bhoumik, Debasmita Majumdar, Ritajit Center for Computational Natural Sciences and Bioinformatics International Institute of Information Technology Hyderabad India Center for Quantum Science and Technology International Institute of Information Technology Hyderabad India Xanadu TorontoONM5G 2C8 Canada Faculty of Mathematics and Computer Science Jagiellonian University Kraków Poland Department of Physics Indian Institute of Technology Dhanbad India Jülich Supercomputing Center Forschungszentrum Jülich Germany RWTH Aachen University Germany Advanced Computing & Microelectronics Unit Indian Statistical Institute Kolkata India

Surface codes are quantum error correcting codes typically defined on 2D array of qubits. In this paper, a [dx,dz] surface code design is being introduced, where dx(dz) represents the distance of the code for bit (phase) error correction, motivated by the fact that the severity of bit flip and phase flip errors in the physical quantum system is asymmetric. We present pseudo-threshold and threshold values for the proposed surface code design for asymmetric error channels in the presence of various degrees of asymmetry of Pauli Xˆ, Ŷ, and Ẑ errors in a depolarization channel. We demonstrate that compared to symmetric surface codes, our asymmetric surface codes can provide almost double the pseudo-threshold rates while requiring less than half the number of physical qubits in the presence of increasing asymmetry in the error channel. Our results show that for low degree of asymmetry, it is advantageous to increase dx along with dz. However, as the asymmetry of the channel increases, higher pseudo-threshold is obtained with increasing dz when dx is kept constant at a low value. Additionally, we also show that the advantage in the pseudo-threshold rates begins to saturate for any possible degree of asymmetry in the error channel as the surface code asymmetry is continued to increase. © 2021, CC BY-NC-ND.

关键词： Error correction

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Multiple descent: Design your own generalization curve

arXiv

引用

arXiv 2020年

作者： Chen, Lin Min, Yifei Belkin, Mikhail Karbasi, Amin Simons Institute for the Theory of Computing University of California Berkeley United States Department of Statistics and Data Science Yale University United States Halıcıoğlu Data Science Institute University of California San Diego United States Department of Electrical Engineering Computer Science Statistics and Data Science Yale University United States

This paper explores the generalization loss of linear regression in variably parameterized families of models, both under-parameterized and over-parameterized. We show that the generalization curve can have an arbitrary number of peaks, and moreover, locations of those peaks can be explicitly controlled. Our results highlight the fact that both classical U-shaped generalization curve and the recently observed double descent curve are not intrinsic properties of the model family. Instead, their emergence is due to the interaction between the properties of the data and the inductive biases of learning algorithms. Copyright © 2020, The Authors. All rights reserved.

关键词： Parameterization

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