IA Scholar Query: Quantum Lower Bound for Graph Collision Implies Lower Bound for Triangle Detection.
https://scholar.archive.org/
Internet Archive Scholar query results feedeninfo@archive.orgTue, 22 Nov 2022 00:00:00 GMTfatcat-scholarhttps://scholar.archive.org/help1440Another Round of Breaking and Making Quantum Money: How to Not Build It from Lattices, and More
https://scholar.archive.org/work/ghlrkjfs2nef5fwmkalccul75i
Public verification of quantum money has been one of the central objects in quantum cryptography ever since Wiesner's pioneering idea of using quantum mechanics to construct banknotes against counterfeiting. So far, we do not know any publicly-verifiable quantum money scheme that is provably secure from standard assumptions. In this work, we provide both negative and positive results for publicly verifiable quantum money. **In the first part, we give a general theorem, showing that a certain natural class of quantum money schemes from lattices cannot be secure. We use this theorem to break the recent quantum money scheme of Khesin, Lu, and Shor. **In the second part, we propose a framework for building quantum money and quantum lightning we call invariant money which abstracts some of the ideas of quantum money from knots by Farhi et al.(ITCS'12). In addition to formalizing this framework, we provide concrete hard computational problems loosely inspired by classical knowledge-of-exponent assumptions, whose hardness would imply the security of quantum lightning, a strengthening of quantum money where not even the bank can duplicate banknotes. **We discuss potential instantiations of our framework, including an oracle construction using cryptographic group actions and instantiations from rerandomizable functional encryption, isogenies over elliptic curves, and knots.Hart Montgomery, Jiahui Liu, Mark Zhandrywork_ghlrkjfs2nef5fwmkalccul75iTue, 22 Nov 2022 00:00:00 GMTQuantum algorithms and the power of forgetting
https://scholar.archive.org/work/iksgkzg52ffc3hyz5dkcnirwmi
The so-called welded tree problem provides an example of a black-box problem that can be solved exponentially faster by a quantum walk than by any classical algorithm. Given the name of a special ENTRANCE vertex, a quantum walk can find another distinguished EXIT vertex using polynomially many queries, though without finding any particular path from ENTRANCE to EXIT. It has been an open problem for twenty years whether there is an efficient quantum algorithm for finding such a path, or if the path-finding problem is hard even for quantum computers. We show that a natural class of efficient quantum algorithms provably cannot find a path from ENTRANCE to EXIT. Specifically, we consider algorithms that, within each branch of their superposition, always store a set of vertex labels that form a connected subgraph including the ENTRANCE, and that only provide these vertex labels as inputs to the oracle. While this does not rule out the possibility of a quantum algorithm that efficiently finds a path, it is unclear how an algorithm could benefit by deviating from this behavior. Our no-go result suggests that, for some problems, quantum algorithms must necessarily forget the path they take to reach a solution in order to outperform classical computation.Andrew M. Childs, Matthew Coudron, Amin Shiraz Gilaniwork_iksgkzg52ffc3hyz5dkcnirwmiTue, 22 Nov 2022 00:00:00 GMTDagstuhl Reports, Volume 12, Issue 4, April 2022, Complete Issue
https://scholar.archive.org/work/oiijemxg5zhmzehjc3gy2mvkhm
Dagstuhl Reports, Volume 12, Issue 4, April 2022, Complete Issuework_oiijemxg5zhmzehjc3gy2mvkhmMon, 14 Nov 2022 00:00:00 GMTExploiting the phenomenology of flavourful Z′ models
https://scholar.archive.org/work/lbdhtaeqzbbozp34kxwinc27tm
This thesis comprises recent studies on extensions of the standard model (SM) involving a heavy Z' boson. In the SM, flavour-changing neutral current (FCNC) quark transitions only appear at loop level and are highly suppressed. This puts forward flavourful Z' models, where the new gauge boson couples non-universally to the known quarks and leptons at tree level. The models are able address the persistent deviations of the SM seen in observables of rare B-meson decays referred to as the B-anomalies. By supplementing the particle content of the SM with new scalars and vector-like fermions, the occurrence of putative Landau poles present in general Z' scenarios can be averted. We discuss dedicated models in the context of the B-anomalies that allow for a stable and predictive theory up to the Planck scale. Moreover, flavour rotations also enable FCNC transitions in the charm sector, where the resonance pollution in branching ratios of semileptonic decays demands null test observables sensitive to physics beyond the SM. We investigate effects in such decays and present unique correlations to CP-violating observables in hadronic decays, accessible with future measurements by the LHCb and Belle II experiments. Recent studies involving dineutrino modes are discussed as well. We exploit an interplay between neutrino and charged lepton couplings within the SM effective field theory approach that connects decays of opposite flavour sectors. In doing so, we derive limits on diverse sets of dineutrino branching ratios and find novel tests of lepton universality using data from global fits of the B-anomalies.Rigo Bause, Technische Universität Dortmundwork_lbdhtaeqzbbozp34kxwinc27tmWed, 09 Nov 2022 00:00:00 GMTTop Quark Asymmetry in boosted single-lepton events at 13 TeV proton-proton collisions
https://scholar.archive.org/work/rriglgewtvfsjlqs6vrf4h4aam
The top quark plays a special role in many Beyond the Standard Model theories that predict new massive particles decaying into a top quark and a top anti-quark pair (tt). Depending on the momentum of massive particles (hundreds of GeV or a few TeV), the decay products may be distributed isotropically or highly collimated. This thesis presents the measurement of the charge asymmetry for highly boosted tt pairs decaying in the single lepton + jets topology. The analysis is performed using 138 fb-1 of data collected in pp collisions at s = 13 TeV with the CMS detector during Run 2 of the Large Hadron Collider. The event selection is optimized for tt pairs produced with large Lorentz- boosts resulting in non-isolated leptons and overlapping jets from the t -> bW -> bqq decay. The top quark charge asymmetry is measured for events with t ̄t invariant mass larger than 750 GeV and corrected for detector and acceptance effects using a binned maximum likelihood fit. The measured value of Ac_full = 0.0069 ± 0.0044(stat)+0.0065(syst) ± 0.0032(MCstat) is 0.0069 in good agreement with the standard model prediction at NNLO in perturbation theory with NLO electroweak corrections. Differential distributions for two invariant mass bins are also presented.Hugo Alberto Becerril Gonzalezwork_rriglgewtvfsjlqs6vrf4h4aamTue, 08 Nov 2022 00:00:00 GMTNdBaInO4 based triple (electronic, ionic and protonic) conductor for solid oxide fuel cell applications
https://scholar.archive.org/work/5wjpqdmzdng7xpuchinkyo2zfu
Oxide-ion conducting materials have never failed to attract intensive attention due to their potential to be used for the applications of solid oxide fuel cell (SOFC) devices. With the aim of reducing the operating temperatures of SOFC devices to the intermediate high temperature range (500oC-800 oC), the design and synthesis of a new structure family to be used as the electrolyte material could be crucial. In this thesis, the potential of calcium-doped layered perovskite compounds, BaNd1-xCaxInO4-x/2 (where x is the Ca content), as protonic conductors was experimentally investigated. The single phase of monoclinic crystal structure with the P21/c symmetry was confirmed in the as-synthesized BaNd1-xCaxInO4-x/2 solid solutions by XRD characterisations. The acceptor-doped ceramics exhibited improved total conductivities that were 1-2 orders of magnitude higher than those of the parent material, BaNdInO4. The highest total conductivity of 2.6 x 10-3 Scm-1 was obtained for the BaNd0.8Ca0.2InO3.90 sample at a temperature of 750 oC in air. Electrochemical impedance spectroscopy measurements of the x = 0.1 and x = 0.2 substituted samples showed higher total conductivity under humid environments than those measured in a dry environment over a large temperature range (250 oC-750 oC). At 500 oC, the total conductivity of the 20% substituted sample in humid air (~3% H2O) was 1.3 x 10-4 Scm-1. The incorporation of water vapour decreased the activation energies of the bulk conductivity of the BaNd0.8Ca0.2InO3.90 sample from 0.755(2) eV to 0.678(2) eV in air. The saturated BaNd0.8Ca0.2InO3.90 sample contained 2.2 mol% protonic defects, which caused an expansion in the lattice according to the in-situ X-ray diffraction data. Combining studies of the impedance behaviour with 4-probe DC conductivity measurements obtained in humid air which showed a decrease in the resistance of the x=0.2 sample, it could be concluded that experimental evidence indicates that BaNd1-xCaxInO4-x/2 exhibits triple (oxygen-ion, proton and hole) conduct [...]Yu Zhou, Stephen Skinner, China Scholarship Councilwork_5wjpqdmzdng7xpuchinkyo2zfuMon, 07 Nov 2022 00:00:00 GMTCommitments to Quantum States
https://scholar.archive.org/work/bwvzrlvhy5dldln6tafuyunbyq
What does it mean to commit to a quantum state? In this work, we propose a simple answer: a commitment to quantum messages is binding if, after the commit phase, the committed state is hidden from the sender's view. We accompany this new definition with several instantiations. We build the first non-interactive succinct quantum state commitments, which can be seen as an analogue of collision-resistant hashing for quantum messages. We also show that hiding quantum state commitments (QSCs) are implied by any commitment scheme for classical messages. All of our constructions can be based on quantum-cryptographic assumptions that are implied by but are potentially weaker than one-way functions. Commitments to quantum states open the door to many new cryptographic possibilities. Our flagship application of a succinct QSC is a quantum-communication version of Kilian's succinct arguments for any language that has quantum PCPs with constant error and polylogarithmic locality. Plugging in the PCP theorem, this yields succinct arguments for NP under significantly weaker assumptions than required classically; moreover, if the quantum PCP conjecture holds, this extends to QMA. At the heart of our security proof is a new rewinding technique for extracting quantum information.Sam Gunn and Nathan Ju and Fermi Ma and Mark Zhandrywork_bwvzrlvhy5dldln6tafuyunbyqSat, 05 Nov 2022 00:00:00 GMTModern Machine Learning for LHC Physicists
https://scholar.archive.org/work/an7b2n4yrbaqnck74hcgbf5chu
Modern machine learning is transforming particle physics, faster than we can follow, and bullying its way into our numerical tool box. For young researchers it is crucial to stay on top of this development, which means applying cutting-edge methods and tools to the full range of LHC physics problems. These lecture notes are meant to lead students with basic knowledge of particle physics and significant enthusiasm for machine learning to relevant applications as fast as possible. They start with an LHC-specific motivation and a non-standard introduction to neural networks and then cover classification, unsupervised classification, generative networks, and inverse problems. Two themes defining much of the discussion are well-defined loss functions reflecting the problem at hand and uncertainty-aware networks. As part of the applications, the notes include some aspects of theoretical LHC physics. All examples are chosen from particle physics publications of the last few years. Given that these notes will be outdated already at the time of submission, the week of ML4Jets 2022, they will be updated frequently.Tilman Plehn, Anja Butter, Barry Dillon, Claudius Krausework_an7b2n4yrbaqnck74hcgbf5chuWed, 02 Nov 2022 00:00:00 GMTUnclonability and Quantum Cryptanalysis: From Foundations to Applications
https://scholar.archive.org/work/rfthbhoi4zcrff65a2fyzhjubq
The impossibility of creating perfect identical copies of unknown quantum systems is a fundamental concept in quantum theory and one of the main non-classical properties of quantum information. This limitation imposed by quantum mechanics, famously known as the no-cloning theorem, has played a central role in quantum cryptography as a key component in the security of quantum protocols. In this thesis, we look at Unclonability in a broader context in physics and computer science and more specifically through the lens of cryptography, learnability and hardware assumptions. We introduce new notions of unclonability in the quantum world, namely quantum physical unclonability, and study the relationship with cryptographic properties and assumptions such as unforgeability, and quantum pseudorandomness. The purpose of this study is to bring new insights into the field of quantum cryptanalysis and into the notion of unclonability itself. We also discuss several applications of this new type of unclonability as a cryptographic resource for designing provably secure quantum protocols. Furthermore, we present a new practical cryptanalysis technique concerning the problem of approximate cloning of quantum states. We design a quantum machine learning-based cryptanalysis algorithm to demonstrate the power of quantum learning tools as both attack strategies and powerful tools for the practical study of quantum unclonability.Mina Doostiwork_rfthbhoi4zcrff65a2fyzhjubqMon, 31 Oct 2022 00:00:00 GMTDipolar physics: A review of experiments with magnetic quantum gases
https://scholar.archive.org/work/nxugmw4bn5egdp22x5va45o3ty
Since the achievement of quantum degeneracy in gases of chromium atoms in 2004, the experimental investigation of ultracold gases made of highly magnetic atoms has blossomed. The field has yielded the observation of many unprecedented phenomena, in particular those in which long-range and anisotropic dipole-dipole interactions play a crucial role. In this review, we aim to present the aspects of the magnetic quantum-gas platform that make it unique for exploring ultracold and quantum physics as well as to give a thorough overview of experimental achievements.Lauriane Chomaz, Igor Ferrier-Barbut, Francesca Ferlaino, Bruno Laburthe-Tolra, Benjamin L. Lev, Tilman Pfauwork_nxugmw4bn5egdp22x5va45o3tyMon, 31 Oct 2022 00:00:00 GMTMolecular recognition and selectivity : computational investigations on the dynamics of non-bonded interactions
https://scholar.archive.org/work/5ypenys5t5fhpa3exfbq6tfheu
Non-bonded interactions, such as hydrogen bonds, as well as hydrophobic and electrostatic interactions determine structure and dynamics of flexible molecules and multi-molecular assemblies. In single molecules, they selectively enable and stabilize rare, energetically unfavorable conformations which facilitate intramolecular chemical reactions or reaction with the solvent molecules. Such reactions often result in changes of surface charges with far-reaching effects on the molecular properties. Additionally, non-bonded interactions mediate the association of molecules to transient aggregates and stable complexes. The complementarity of interaction donors and acceptors on two molecular surfaces is the basis for their pairwise recognition. Selective recognition of distinct molecules or chemical groups within a single molecule is a fundamental aspect of cellular life as well as of artificial chemical systems. Experimental methods often measure the macroscopic consequences of non-bonded interactions instead of the interaction themselves. More elaborate techniques are expensive and error-prone and still only yield limited insight. An experimental means to assess molecular interactions with high spatial and temporal resolution has not yet been proposed. In recent years, with the rise of graphics processing units and the increase in easily available computing power, the theoretical Molecular Dynamics (MD) method has emerged as standard tool to investigate the time-resolved behavior of molecular structures and interactions. A cornucopia of condensed phase molecular systems has been to the subject of MD simulations, yet with varying rigor in preparation, force-field selection, and quantitative analysis. Even though different questions require different analytics, an absence of comparable, generally applicable means to analyze and visualize non-bonded interactions and their effects from MD trajectory data can be stated. In this work, dynamical aspects of non-bonded interactions as the basis for molecular selectivity and rec [...]Eric Schulze-Niemand, Universitäts- Und Landesbibliothek Sachsen-Anhalt, Martin-Luther Universität, Michael Naumannwork_5ypenys5t5fhpa3exfbq6tfheuMon, 24 Oct 2022 00:00:00 GMT0-Form, 1-Form and 2-Group Symmetries via Cutting and Gluing of Orbifolds
https://scholar.archive.org/work/qdzmyyzfqfdxvncco3cpnlqsxm
Orbifold singularities of M-theory constitute the building blocks of a broad class of supersymmetric quantum field theories (SQFTs). In this paper we show how the local data of these geometries determines global data on the resulting higher symmetries of these systems. In particular, via a process of cutting and gluing, we show how local orbifold singularities encode the 0-form, 1-form and 2-group symmetries of the resulting SQFTs. Geometrically, this is obtained from the possible singularities which extend to the boundary of the non-compact geometry. The resulting category of boundary conditions then captures these symmetries, and is equivalently specified by the orbifold homology of the boundary geometry. We illustrate these general points in the context of a number of examples, including 5D superconformal field theories engineered via orbifold singularities, 5D gauge theories engineered via singular elliptically fibered Calabi-Yau threefolds, as well as 4D SQCD-like theories engineered via M-theory on non-compact G_2 spaces.Mirjam Cvetič, Jonathan J. Heckman, Max Hübner, Ethan Torreswork_qdzmyyzfqfdxvncco3cpnlqsxmWed, 19 Oct 2022 00:00:00 GMTUnitary property testing lower bounds by polynomials
https://scholar.archive.org/work/gvdl6nb2nvhgzndhqei7gawomm
We study unitary property testing, where a quantum algorithm is given query access to a black-box unitary and has to decide whether it satisfies some property. In addition to containing the standard quantum query complexity model (where the unitary encodes a binary string) as a special case, this model contains "inherently quantum" problems that have no classical analogue. Characterizing the query complexity of these problems requires new algorithmic techniques and lower bound methods. Our main contribution is a generalized polynomial method for unitary property testing problems. By leveraging connections with invariant theory, we apply this method to obtain lower bounds on problems such as determining recurrence times of unitaries, approximating the dimension of a marked subspace, and approximating the entanglement entropy of a marked state. We also present a unitary property testing-based approach towards an oracle separation between 𝖰𝖬𝖠 and 𝖰𝖬𝖠(2), a long standing question in quantum complexity theory.Adrian She, Henry Yuenwork_gvdl6nb2nvhgzndhqei7gawommWed, 12 Oct 2022 00:00:00 GMT5. To Be or Not to Be a Patient
https://scholar.archive.org/work/4ua7hnpn35c6lgy4ubb2xuozb4
and head of the research group CLIMAS. A specialist of American modernism and naturalism, she has published books and articles on F. Scott Fitzgerald, Nathanael West, Frank Norris and Stephen Crane. For several years now, she has focused her research on the representation of illness in literature and published numerous articles on the subject in French, European and American journals. Recently, she has developed a special interest in the neuronovel, and published several articles, a special issue of EJAS, and a Wiley encyclopedia entry on brain fiction.Pascale Antolinwork_4ua7hnpn35c6lgy4ubb2xuozb4Tue, 11 Oct 2022 00:00:00 GMTFundamentals of electroweak theory
https://scholar.archive.org/work/gdgl5lxejfcbxoxnmwebnqgs64
The present text is an updated version of an earlier author's book on the electroweak theory (published originally in 2002, ISBN 80-246-0639-9). It reflects the ultimate completion of the standard model by the long-awaited discovery of the Higgs boson (ten years after the first edition) and incorporates also some minor corrections of the previous text, removing typos, etc. As regards an immediate motivation to come up with such an update of the original rather old book, the 10th anniversary of the Higgs boson discovery seems to be an opportune moment for doing it now. The publication of the current upgraded text within the e-print arXiv is aimed at its best possible availability for any interested reader.Jiri Horejsiwork_gdgl5lxejfcbxoxnmwebnqgs64Mon, 10 Oct 2022 00:00:00 GMTNonadiabatic Landau-Zener-Stückelberg-Majorana transitions, dynamics, and interference
https://scholar.archive.org/work/ba3l6el3efckzkh4amiuxwdngu
Since the pioneering works by Landau, Zener, St\"uckelberg, and Majorana (LZSM), it has been known that driving a quantum two-level system results in tunneling between its states. Even though the interference between these transitions is known to be important, it is only recently that it became both accessible, controllable, and useful for engineering quantum systems. Here, we study systematically various aspects of LZSM physics and review the relevant literature, significantly expanding the review article in [Shevchenko, S. N., S. Ashhab, and F. Nori (2010), "Landau-Zener-St\"uckelberg interferometry," Phys. Rep. 492, 1].Oleh V. Ivakhnenko, Sergey N. Shevchenko, Franco Noriwork_ba3l6el3efckzkh4amiuxwdnguMon, 03 Oct 2022 00:00:00 GMTApplications of Persistent Homology in Nuclear Collisions
https://scholar.archive.org/work/4almflodbzdtxmsyk6wf4fp7he
We introduce a novel set of observables associated to the rapidly developing field of persistent homology for the quantitative characterization of nuclear collisions and their evolution. Persistent homology allows for the identification of topological and homological characteristics of distributions in multi-dimensional spaces. We demonstrate here how to apply the toolset of persistent homology to the extraction of novel clustering signatures and the identification of long-range flow correlations in the particle production process of nuclear collisions.Greg Hamilton, Travis Dore, Christopher Plumbergwork_4almflodbzdtxmsyk6wf4fp7heFri, 30 Sep 2022 00:00:00 GMTAn integrated geological-geophysical approach to subsurface interface reconstruction of muon tomography measurements in high alpine regions
https://scholar.archive.org/work/ricux5erhrhe7dhkcevl5l3iuy
Muon tomography is an imaging technique that emerged in the last decades. The principal concept is similar to X-ray tomography, where one determines the spatial distribution of material densities by means of penetrating photons. It differs from this well-known technology only by the type of particle. Muons are continuously produced in the Earth's atmosphere when primary cosmic rays (mostly protons) interact with the atmosphere's molecules. Depending on their energies these muons can penetrate materials up to several hundreds of metres (or even kilometres). Consequently, they have been used for the imaging of larger objects, including large geological objects such as volcanoes, caves and fault systems. This research project aimed at applying this technology to an alpine glacier in Central Switzerland to determine its bedrock geometry, and if possible, to gain information on the bedrock erosion mechanism. To this end, two major experimental studies have been conducted with the aim to reconstruct bedrock geometries of two different glaciers. Given this framework, I present in this thesis my contribution to the project in which I worked for 5 years. Most of the technological know-how of muon tomography still lies within physics institutes who were the key drivers in the development of this method. As the geophysical/geological community is nowadays an important user of this technology, it is important that also non-physicists familiarise themselves with the theory and concepts behind muon tomography. This can be seen as an effective method to bring more geoscientists to utilize this new technology for their own research. The first part of this thesis is designed to tackle this problem with a review article on the principles of muon tomography and a guide to best practice. A second important aspect is the reconstruction of the bedrock topography given muon flux measurements at various locations. Many to-date reconstruction algorithms include supplementary geological information such as density and/or compositional me [...]Alessandro Diego Lechmannwork_ricux5erhrhe7dhkcevl5l3iuyThu, 29 Sep 2022 00:00:00 GMTTesting Explanations of Short Baseline Neutrino Anomalies
https://scholar.archive.org/work/ojolauja4fe3doblxx4sl4cr4e
The experimental observation of neutrino oscillations profoundly impacted the physics of neutrinos, from being well understood theoretically to requiring new physics beyond the standard model of particle physics. Indeed, the mystery of neutrino masses implies the presence of new particles never observed before, often called sterile neutrinos, as they would not undergo standard weak interactions. And while neutrino oscillation measurements entered the precision era, reaching percent-level precision, many experimental results show significant discrepancies with the standard model, at baselines much shorter than typical oscillation baselines, like LSND, MiniBooNE, gallium experiments, and reactor antineutrino measurements. These short baseline anomalies could be explained by the addition of a light sterile neutrino, with mass in the 1-10 eV range, however, in strong tension with many null experimental observations. Other explanations that rely on sterile neutrinos with masses in the 1-500 MeV could resolve the tension. Here we test both classes of models. On the one hand, we look for datasets collected at a short baseline which can constrain heavy sterile neutrino models. We find that the minimal model is fully constrained, but several extensions of this model could weaken the current constraint and be tested with current and future datasets. On the other hand, we test the presence of neutrino oscillations at short baselines, induced by a light sterile state, with the data collected by the MicroBooNE experiment, a liquid argon time projection chamber specifically designed to resolve the details of each neutrino interaction. We report null results from both analyses, further constraining the space of possible explanations for the short baseline anomalies. If new physics lies behind the short baseline anomaly puzzle, it is definitely not described by a simple model.Nicolò Foppianiwork_ojolauja4fe3doblxx4sl4cr4eTue, 27 Sep 2022 00:00:00 GMTOut-of-time-order correlators and quantum chaos
https://scholar.archive.org/work/hiemjbycdzcdtlu2hrhtw3fada
Quantum Chaos has originally emerged as the field which studies how the properties of classical chaotic systems arise in their quantum counterparts. The growing interest in quantum many-body systems, with no obvious classical meaning has led to consider time-dependent quantities that can help to characterize and redefine Quantum Chaos. This article reviews the prominent role that the out of time ordered correlator (OTOC) plays to achieve such goal.Ignacio García-Mata, Rodolfo A. Jalabert, Diego A. Wisniackiwork_hiemjbycdzcdtlu2hrhtw3fadaFri, 16 Sep 2022 00:00:00 GMT