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Reduction theorem for secrecy over linear network code for active attacks

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arXiv 2020年

作者： Hayashi, Masahito Owari, Masaki Kato, Go Cai, Ning Graduate School of Mathematics Nagoya University Nagoya464-8602 Japan Shenzhen Institute for Quantum Science and Engineering Southern University of Science and Technology Shenzhen518055 China Center for Quantum Computing Peng Cheng Laboratory Shenzhen518000 China Centre for Quantum Technologies National University of Singapore 3 Science Drive 2 117542 Singapore Department of Computer Science Faculty of Informatics Shizuoka University Japan NTT Communication Science Laboratories NTT Corporation Japan School of Information Science and Technology ShanghaiTech University Middle Huaxia Road no 393 Pudong Shanghai201210 China

We discuss the effect of sequential error injection on information leakage under a network code. We formulate a network code for the single transmission setting and the multiple transmission setting. Under this formulation, we show that the eavesdropper cannot improve the power of eavesdropping by sequential error injection when the operations in the network are linear *** demonstrate the usefulness of this reduction theorem by applying a concrete example of network. Copyright © 2020, The Authors. All rights reserved.

关键词： Network coding

Speed of quantum information spreading in chaotic systems

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Physical Review B 2020年第4期102卷 045114-045114页

作者： Josiah Couch Stefan Eccles Phuc Nguyen Brian Swingle Shenglong Xu Weinberg Theory Group Department of Physics The University of Texas at Austin Austin Texas 78712 USA Maryland Center for Fundamental Physics University of Maryland College Park Maryland 20742 USA Condensed Matter Theory Center Maryland Center for Fundamental Physics Joint Institute for Quantum Information and Computer Science and Department of Physics University of Maryland College Park Maryland 20742 USA Condensed Matter Theory Center and Department of Physics University of Maryland College Park Maryland 20742 USA and Department of Physics & Astronomy Texas A&M University College Station Texas 77843 USA

We present a general theory of quantum information propagation in chaotic quantum many-body systems. The generic expectation in such systems is that quantum information does not propagate in localized form; instead, it tends to spread out and scramble into a form that is inaccessible to local measurements. To characterize this spreading, we define an information speed via a quench-type experiment and derive a general formula for it as a function of the entanglement density of the initial state. As the entanglement density varies from zero to one, the information speed varies from the entanglement speed to the butterfly speed. We verify that the formula holds both for a quantum chaotic spin chain and in field theories with an AdS/CFT gravity dual. For the second case, we study in detail the dynamics of entanglement in two-sided Vaidya-AdS-Reissner-Nordstrom black branes. We also show that, with an appropriate decoding process, quantum information can be construed as moving at the information speed, and, in the case of AdS/CFT, we show that a locally detectable signal propagates at the information speed in a spatially local variant of the traversable wormhole setup.

关键词： Entanglement entropy Gauge-gravity dualities quantum quench Spin chains

CONVEX CONES IN MAPPING SPACES BETWEEN MATRIX ALGEBRAS

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arXiv 2020年

作者： Girard, Mark Kye, Seung-Hyeok Størmer, Erling Institute for Quantum Computing School of Computer Science University of Waterloo WaterlooONN2L 3G1 Canada Department of Mathematics Institute of Mathematics Seoul National University Seoul151-742 Korea Republic of Department of Mathematics University of Oslo Oslo0316 Norway

We introduce the notion of one-sided mapping cones of positive linear maps between matrix algebras. These are convex cones of maps that are invariant under compositions by completely positive maps from either the left or right side. The duals of such convex cones can be characterized in terms of ampliation maps, which can also be used to characterize many notions from quantum information theory-such as separability, entanglement-breaking maps, Schmidt numbers, as well as decomposable maps and k-positive maps in functional analysis. In fact, such characterizations hold if and only if the involved cone is a one-sided mapping cone. Through this analysis, we obtain mapping properties for compositions of cones from which we also obtain several equivalent statements of the PPT (positive partial transpose) square *** Codes 15A30, 81P15, 46L05, 46L07 © 2020, CC BY-NC-SA.

关键词： Matrix algebra

Spinfoam on Lefschetz thimble: Markov chain Monte-Carlo computation of Lorentzian spinfoam propagator

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arXiv 2020年

作者： Han, Muxin Huang, Zichang Liu, Hongguang Qu, Dongxue Wan, Yidun Department of Physics Florida Atlantic University 777 Glades Road Boca RatonFL33431-0991 United States Institut für Quantengravitation Universität Erlangen-Nürnberg Staudtstr. 7/B2 Erlangen91058 Germany State Key Laboratory of Surface Physics Fudan University Shanghai200433 China Department of Physics Center for Field Theory and Particle Physics Institute for Nanoelectronic devices and Quantum computing Fudan University Shanghai200433 China State Key Laboratory of Surface Physics Fudan University Shanghai200433 China Department of Physics Center for Field Theory and Particle Physics Institute for Nanoelectronic devices and Quantum computing Fudan University Shanghai200433 China Department of Physics Institute for Quantum Science and Engineering Southern University of Science and Technology Shenzhen518055 China

We compute numerically the Lorentzian Engle-Pereira-Rovelli-Livine (EPRL) spinfoam propagator on a 4-simplex, by adapting the methods of Lefschetz thimble and Markov Chain Monte-Carlo to oscillatory spinfoam integrals. Our method can compute any spinfoam observables at relatively large spins. We obtain the numerical results of the propagators at different spins and demonstrate their consistency with the expected spinfoam semi-classical behavior in the large spin limit. Our results exhibit significant quantum corrections at smaller spins. Our method is reliable and thus can be employed to discover the semi-classical and quantum behaviors of the spinfoam model. Copyright © 2020, The Authors. All rights reserved.

关键词： Monte Carlo methods

Rigidity of superdense coding

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arXiv 2020年

作者： Nayak, Ashwin Yuen, Henry Department of Combinatorics and Optimization Institute for Quantum Computing University of Waterloo 200 University Ave. W. WaterlooONN2L 3G1 Canada Department of Computer Science Columbia University New York United States

The famous superdense coding protocol of Bennett and Wiesner demonstrates that it is possible to communicate two bits of classical information by sending only one qubit and using a shared EPR pair. Our first result is that an arbitrary protocol for achieving this task (where there are no assumptions on the sender’s encoding operations or the dimension of the shared entangled state) is locally equivalent to the canonical Bennett-Wiesner protocol. In other words, the superdense coding task is rigid. In particular, we show that the sender and receiver only use additional entanglement (beyond the EPR pair) as a source of classical randomness. We also investigate several questions about higher-dimensional superdense coding, where the goal is to communicate one of d2 possible messages by sending a d-dimensional quantum state, for general dimensions d. Unlike the d = 2 case (i.e. sending a single qubit), there can be inequivalent superdense coding protocols for higher d. We present concrete constructions of inequivalent protocols, based on constructions of inequivalent orthogonal unitary bases for all d > 2. Finally, we analyze the performance of superdense coding protocols where the encoding operators are independently sampled from the Haar measure on the unitary group. Our analysis involves bounding the distinguishability of random maximally entangled states, which may be of independent interest. © 2020, CC BY.

关键词： quantum entanglement

Experimental optimal orienteering via parallel and antiparallel spins

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arXiv 2020年

作者： Tang, Jun-Feng Hou, Zhibo Shang, Jiangwei Zhu, Huangjun Xiang, Guo-Yong Li, Chuan-Feng Guo, Guang-Can Key Laboratory of Quantum Information University of Science and Technology of China CAS Hefei230026 China Synergetic Innovation Center of Quantum Information and Quantum Physics University of Science and Technology of China Hefei230026 China Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement of Ministry of Education School of Physics Beijing Institute of Technology Beijing100081 China Department of Physics Center for Field Theory and Particle Physics Fudan University Shanghai200433 China State Key Laboratory of Surface Physics Fudan University Shanghai200433 China Institute for Nanoelectronic Devices and Quantum Computing Fudan University Shanghai200433 China Collaborative Innovation Center of Advanced Microstructures Nanjing210093 China

Antiparallel spins are superior in orienteering to parallel spins. This intriguing phenomenon is tied to entanglement associated with quantum measurements rather than quantum states. Using photonic systems, we experimentally realize the optimal orienteering protocols based on parallel spins and antiparallel spins, respectively. The optimal entangling measurements for decoding the direction information from parallel spins and antiparallel spins are realized using photonic quantum walks, which is a useful idea that is of wide interest in quantum information processing and foundational studies. Our experiments clearly demonstrate the advantage of antiparallel spins over parallel spins in orienteering. In addition, entangling measurements can extract more information than local measurements even if no entanglement is present in the quantum states. Copyright © 2020, The Authors. All rights reserved.

关键词： quantum entanglement

Inclusive jet and hadron suppression in a multistage approach

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Physical Review C 2023年第3期107卷 034911-034911页

作者： A. Kumar Y. Tachibana C. Sirimanna G. Vujanovic S. Cao A. Majumder Y. Chen L. Du R. Ehlers D. Everett W. Fan Y. He J. Mulligan C. Park A. Angerami R. Arora S. A. Bass T. Dai H. Elfner R. J. Fries C. Gale F. Garza M. Heffernan U. Heinz B. V. Jacak P. M. Jacobs S. Jeon K. Kauder L. Kasper W. Ke M. Kelsey B. Kim M. Kordell, II J. Latessa Y.-J. Lee D. Liyanage A. Lopez M. Luzum S. Mak A. Mankolli C. Martin H. Mehryar T. Mengel C. Nattrass D. Oliinychenko J.-F. Paquet J. H. Putschke G. Roland B. Schenke L. Schwiebert A. Sengupta C. Shen A. Silva D. Soeder R. A. Soltz J. Staudenmaier M. Strickland J. Velkovska X.-N. Wang R. L. Wolpert Department of Physics McGill University Montréal Quebec H3A 2T8 Canada Department of Physics and Astronomy Wayne State University Detroit Michigan 48201 USA Akita International University Yuwa Akita-city 010-1292 Japan Department of Physics University of Regina Regina Saskatchewan S4S 0A2 Canada 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 and Astronomy University of Tennessee Knoxville Tennessee 37996 USA Physics Division Oak Ridge National Laboratory Oak Ridge Tennessee 37830 USA Department of Physics The Ohio State University Columbus Ohio 43210 USA Department of Physics Duke University Durham North Carolina 27708 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 University of California Berkeley California 94270 USA Nuclear Science Division Lawrence Berkeley National Laboratory Berkeley California 94270 USA 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 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 Department of Physics

We present a new study of jet interactions in the quark-gluon plasma created in high-energy heavy-ion collisions, using a multistage event generator within the jetscape framework. We focus on medium-induced modifications in the rate of inclusive jets and high transverse momentum (high-pT) hadrons. Scattering-induced jet energy loss is calculated in two stages: a high virtuality stage based on the matter model, in which scattering of highly virtual partons modifies the vacuum radiation pattern, and a second stage at lower jet virtuality based on the lbt model, in which leading partons gain and lose virtuality by scattering and radiation. Coherence effects that reduce the medium-induced emission rate in the matter phase are also included. The trento model is used for initial conditions, and the (2+1)dimensional vishnu model is used for viscous hydrodynamic evolution. Jet interactions with the medium are modeled via 2-to-2 scattering with Debye screened potentials, in which the recoiling partons are tracked, hadronized, and included in the jet clustering. Holes left in the medium are also tracked and subtracted to conserve transverse momentum. Calculations of the nuclear modification factor (RAA) for inclusive jets and high-pT hadrons are compared to experimental measurements at the BNL Relativistic Heavy Ion Collider (RHIC) and the CERN Large Hadron Collider (LHC). Within this framework, we find that with one extra parameter which codifies the transition between stages of jet modification—along with the typical parameters such as the coupling in the medium, the start and stop criteria, etc.—we can describe these data at all energies for central and semicentral collisions without a rescaling of the jet transport coefficient q̂.

关键词： Hard scattering Hydrodynamic models Jets & heavy flavor physics quantum chromodynamics Quark & gluon jets Quark-gluon plasma Relativistic heavy-ion collisions

Are lateral lipid-phase diffusion coefficients pertinent to dermal absorption?

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Journal of controlled release : official journal of the Controlled Release Society 2025年 113773页

作者： Junxi Wang Arne Nägel Gerald B Kasting Johannes M Nitsche Modular Supercomputing and Quantum Computing Institute of Computer Science Goethe University Kettenhofweg 139 60325 Frankfurt a.M. Germany. James L. Winkle College of Pharmacy University of Cincinnati Academic Health Center Cincinnati OH 45267-0514 USA. Department of Chemical and Biological Engineering University at Buffalo The State University of New York Buffalo NY 14260-4200 USA. Electronic address: nitsche@buffalo.edu.

The skin's outer barrier layer, the stratum corneum (SC), is comprised of keratin-rich corneocytes, connected by proteinaceous corneodesmosomes and separated by nonpolar, lamellar lipids. The lipids are inherently anisotropic due to their lamellar organization. There is growing acceptance that this structural anisotropy carries over into transport properties including diffusive mass transport, which is consequently characterized by two diffusion coefficients, D for lateral diffusion along the lipid lamellae and D for transverse diffusion across them. Many microscopic models of SC transport have focused on D, as it is easier to measure and intuitively important if one considers the intervening corneocytes to be impermeable "bricks." However, the latter concept crumbles under close observation, and the weight of evidence shows that the corneocyte phase of the SC is considerably more permeable to most solutes than are the intercellular lipids. Given this finding and a plausible organization of the SC lipids at corneocyte boundaries, the ratio determines the balance of transcellular versus intercellular diffusion. Based on a detailed microscopic analysis of solute diffusion within the SC, we conclude that passive transdermal permeation is affected to only a modest degree (within a factor of ∼2) by the value of D over the full range of values typically encountered. This statement applies to all but highly lipophilic solutes, i.e., to solutes with logK≲5. The transverse diffusivity D is a much more quantitatively influential parameter affecting macroscopically observable diffusion in the transdermal direction. Consequently, D is the diffusivity that should be used in nondimensionalizing SC diffusion models to reduce computational burden. Furthermore, the analysis lends additional support to previous findings from several groups that transcellular diffusion is the dominant mechanism for passive transdermal permeation for all but the most lipophilic and the most hydrophilic

关键词： Anisotropic diffusion Brick-and-mortar models Dermal absorption Intercellular lipid Lateral diffusion Mathematical model Stratum corneum Transverse diffusion

Tensor network models of AdS/qCFT

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arXiv 2020年

作者： Jahn, Alexander Zimborás, Zoltán Eisert, Jens Dahlem Center for Complex Quantum Systems Freie Universität Berlin Berlin14195 Germany Institute for Quantum Information and Matter California Institute of Technology PasadenaCA91125 United States Institute for Particle and Nuclear Physics Wigner Research Centre for Physics Budapest1121 Hungary BME-MTA Lendület Quantum Information Theory Research Group Budapest1111 Hungary Institute for Mathematics Budapest University of Technology and Economics Budapest1111 Hungary Department of Mathematics and Computer Science Freie Universität Berlin Berlin14195 Germany

The study of critical quantum many-body systems through conformal field theory (CFT) is one of the pillars of modern quantum physics. Certain CFTs are also understood to be dual to higher-dimensional theories of gravity via the anti-de Sitter/conformal field theory (AdS/CFT) correspondence. To reproduce various features of AdS/CFT, a large number of discrete models based on tensor networks have been proposed. Some recent models, most notably including toy models of holographic quantum error correction, are constructed on regular time-slice discretizations of AdS. In this work, we show that the symmetries of these models are well suited for approximating CFT states, as their geometry enforces a discrete subgroup of conformal symmetries. Based on these symmetries, we introduce the notion of a quasiperiodic conformal field theory (qCFT), a critical theory less restrictive than full CFT with characteristic multi-scale quasiperiodicity. We discuss holographic code states and their renormalization group flow as specific implementations of a qCFT with fractional central charges and argue that their behavior generalizes to a large class of existing and future models. Beyond approximating CFT properties, we show that these can be best understood as belonging to a new paradigm of discrete holography. Copyright © 2020, The Authors. All rights reserved.

关键词： Tensors