85,483 results match your criteria Physical review letters[Journal]


Destabilization of Local Minima in Analog Spin Systems by Correction of Amplitude Heterogeneity.

Phys Rev Lett 2019 Feb;122(4):040607

Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan.

The relaxation of binary spins to analog values has been the subject of much debate in the field of statistical physics, neural networks, and more recently quantum computing, notably because the benefits of using an analog state for finding lower energy spin configurations are usually offset by the negative impact of the improper mapping of the energy function that results from the relaxation. We show that it is possible to destabilize trapping sets of analog states that correspond to local minima of the binary spin Hamiltonian by extending the phase space to include error signals that correct amplitude inhomogeneity of the analog spin states and controlling the divergence of their velocity. Performance of the proposed analog spin system in finding lower energy states is competitive against state-of-the-art heuristics. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.040607DOI Listing
February 2019

Nonclassicality as a Quantifiable Resource for Quantum Metrology.

Phys Rev Lett 2019 Feb;122(4):040503

Center for Macroscopic Quantum Control and Institute of Applied Physics, Department of Physics and Astronomy, Seoul National University, Seoul 151-742, Korea.

We establish the nonclassicality of continuous-variable states as a resource for quantum metrology. Based on the quantum Fisher information of multimode quadratures, we introduce the metrological power as a measure of nonclassicality with a concrete operational meaning of displacement sensitivity beyond the classical limit. This measure belongs to the resource theory of nonclassicality, which is nonincreasing under linear optical elements. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.040503DOI Listing
February 2019

Tuning of Magnetic Activity in Spin-Filter Josephson Junctions Towards Spin-Triplet Transport.

Phys Rev Lett 2019 Feb;122(4):047002

Dipartimento di Fisica E. Pancini, Università degli Studi di Napoli Federico II, Monte S. Angelo, via Cinthia, I-80126 Napoli, Italy.

The study of superconductor-ferromagnet interfaces has generated great interest in the last decades, leading to the observation of spin-aligned triplet supercurrents and 0-π transitions in Josephson junctions where two superconductors are separated by an itinerant ferromagnet. Recently, spin-filter Josephson junctions with ferromagnetic barriers have shown unique transport properties, when compared to standard metallic ferromagnetic junctions, due to the intrinsically nondissipative nature of the tunneling process. Here we present the first extensive characterization of spin polarized Josephson junctions down to 0. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.047002DOI Listing
February 2019

Analytically Solvable Renormalization Group for the Many-Body Localization Transition.

Phys Rev Lett 2019 Feb;122(4):040601

IST Austria, Am Campus 1, 3400 Klosterneuburg, Austria.

We introduce a simple, exactly solvable strong-randomness renormalization group (RG) model for the many-body localization (MBL) transition in one dimension. Our approach relies on a family of RG flows parametrized by the asymmetry between thermal and localized phases. We identify the physical MBL transition in the limit of maximal asymmetry, reflecting the instability of MBL against rare thermal inclusions. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.040601DOI Listing
February 2019
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Probing Quantum Thermalization of a Disordered Dipolar Spin Ensemble with Discrete Time-Crystalline Order.

Phys Rev Lett 2019 Feb;122(4):043603

Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.

We investigate thermalization dynamics of a driven dipolar many-body quantum system through the stability of discrete time crystalline order. Using periodic driving of electronic spin impurities in diamond, we realize different types of interactions between spins and demonstrate experimentally that the interplay of disorder, driving, and interactions leads to several qualitatively distinct regimes of thermalization. For short driving periods, the observed dynamics are well described by an effective Hamiltonian which sensitively depends on interaction details. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.043603DOI Listing
February 2019

Doping-Induced Second-Harmonic Generation in Centrosymmetric Graphene from Quadrupole Response.

Phys Rev Lett 2019 Feb;122(4):047401

State Key Laboratory of Surface Physics, Key Laboratory of Micro and Nano Photonic Structures (MOE), Department of Physics, and Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China.

For centrosymmetric materials such as monolayer graphene, no optical second-harmonic generation (SHG) is generally expected, because it is forbidden under the electric-dipole approximation. Yet we observe a strong, doping-induced SHG from graphene, with its highest strength comparable to the electric-dipole-allowed SHG in noncentrosymmetric 2D materials. This novel SHG has the nature of an electric-quadrupole response, arising from the effective breaking of inversion symmetry by optical dressing with an in-plane photon wave vector. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.047401DOI Listing
February 2019

Extractable Work, the Role of Correlations, and Asymptotic Freedom in Quantum Batteries.

Phys Rev Lett 2019 Feb;122(4):047702

Istituto Italiano di Tecnologia, Graphene Labs, Via Morego 30, I-16163 Genova, Italy.

We investigate a quantum battery made of N two-level systems, which is charged by an optical mode via an energy-conserving interaction. We quantify the fraction of energy stored in the battery that can be extracted in order to perform thermodynamic work. We first demonstrate that this quantity is highly reduced by the presence of correlations between the charger and the battery or between the subsystems composing the battery. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.047702DOI Listing
February 2019

Matter-Wave Diffraction from a Periodic Array of Half Planes.

Phys Rev Lett 2019 Feb;122(4):040401

Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea.

We report on reflection and diffraction of beams of He and D_{2} from square-wave gratings of a 400-μm period and strip widths ranging from 10 to 200  μm at grazing-incidence conditions. In each case we observe fully resolved matter-wave diffraction patterns including the specular reflection and diffracted beams up to the second diffraction order. With decreasing strip width, the observed diffraction efficiencies exhibit a transformation from the known regime of quantum reflection from the grating strips to the regime of edge diffraction from a half-plane array. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.040401DOI Listing
February 2019

DNA Crookedness Regulates DNA Mechanical Properties at Short Length Scales.

Phys Rev Lett 2019 Feb;122(4):048102

Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain.

Sequence-dependent DNA conformation and flexibility play a fundamental role in the specificity of DNA-protein interactions. Here we quantify the DNA crookedness: a sequence-dependent deformation of DNA that consists of periodic bends of the base pair centers chain. Using extensive 100  μs-long, all-atom molecular dynamics simulations, we found that DNA crookedness and its associated flexibility are bijective, which unveils a one-to-one relation between DNA structure and dynamics. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.048102DOI Listing
February 2019

Bond-Disordered Spin Liquid and the Honeycomb Iridate H_{3}LiIr_{2}O_{6}: Abundant Low-Energy Density of States from Random Majorana Hopping.

Phys Rev Lett 2019 Feb;122(4):047202

School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA.

The 5d-electron honeycomb compound H_{3}LiIr_{2}O_{6} [K. Kitagawa et al., Nature (London) 554, 341 (2018)NATUAS0028-083610. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.047202DOI Listing
February 2019

Quantum Machine Learning in Feature Hilbert Spaces.

Phys Rev Lett 2019 Feb;122(4):040504

Xanadu, 372 Richmond Street West, Toronto M5V 2L7, Canada.

A basic idea of quantum computing is surprisingly similar to that of kernel methods in machine learning, namely, to efficiently perform computations in an intractably large Hilbert space. In this Letter we explore some theoretical foundations of this link and show how it opens up a new avenue for the design of quantum machine learning algorithms. We interpret the process of encoding inputs in a quantum state as a nonlinear feature map that maps data to quantum Hilbert space. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.040504DOI Listing
February 2019

First Detection of Scale-Dependent Linear Halo Bias in N-Body Simulations with Massive Neutrinos.

Phys Rev Lett 2019 Feb;122(4):041302

Center for Computational Astrophysics, Flatiron Institute, 162 5th Avenue, New York, New York 10010, USA.

Using N-body simulations with massive neutrino density perturbations, we detect the scale-dependent linear halo bias with high significance. This is the first time that this effect is detected in simulations containing neutrino density perturbations on all scales, confirming the same finding from separate universe simulations. The scale dependence is the result of the additional scale in the system, i. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.041302DOI Listing
February 2019

Sparse Game Changers Restore Collective Motion in Panicked Human Crowds.

Phys Rev Lett 2019 Feb;122(4):048002

Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai 600036, India.

Using a dynamic variant of the Vicsek model, we show that the emergence of disorder from an orderly moving human crowd is a nonequilibrium first-order phase transition. We also show that this transition can be reversed by modifying the dynamics of a few agents, deemed as game changers. Surprisingly, the optimal placement of these game changers is found to be in regions of maximum local crowd speed. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.048002DOI Listing
February 2019

Melting of the Vortex Lattice through Intermediate Hexatic Fluid in an a-MoGe Thin Film.

Phys Rev Lett 2019 Feb;122(4):047001

Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India.

The hexatic fluid refers to a phase in between a solid and a liquid that has short-range positional order but quasi-long-range orientational order. In the celebrated theory of Berezinskii, Kosterlitz, and Thouless and subsequently refined by Halperin, Nelson, and Young, it was predicted that a two-dimensional hexagonal solid can melt in two steps: first, through a transformation from a solid to a hexatic fluid, which retains quasi-long-range orientational order; and then from a hexatic fluid to an isotropic liquid. In this Letter, using a combination of real space imaging and transport measurements, we show that the two-dimensional vortex lattice in an a-MoGe thin film follows this sequence of melting as the magnetic field is increased. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.047001DOI Listing
February 2019

Direct Observation of Anapoles by Neutron Diffraction.

Phys Rev Lett 2019 Feb;122(4):047203

Diamond Light Source, Didcot, OX11 0DE, United Kingdom.

The scope of magnetic neutron scattering has been expanded by the observation of electronic Dirac dipoles (anapoles) that are polar (parity odd) and magnetic (time odd). A zero-magnetization ferromagnet Sm_{0.976}Gd_{0. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.047203DOI Listing
February 2019
2 Reads

Quantum Turbulent Structure in Light.

Phys Rev Lett 2019 Feb;122(4):044301

Department of Physics & Astronomy, University of Denver, Denver, Colorado 80210, USA.

The infinite superpositions of random plane waves are known to be threaded with vortex line singularities which form complicated tangles and obey strict topological rules. We observe that within these structures, a timelike axis appears to emerge with which we can define vortex velocities in a useful way: With both numerical simulations and optical experiments, we show that the statistics of these velocities match those of turbulent quantum fluids such as superfluid helium and atomic Bose-Einstein condensates. These statistics are shown to be independent of system scale. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.044301DOI Listing
February 2019

Periodic Orbits, Entanglement, and Quantum Many-Body Scars in Constrained Models: Matrix Product State Approach.

Phys Rev Lett 2019 Feb;122(4):040603

Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.

We analyze quantum dynamics of strongly interacting, kinetically constrained many-body systems. Motivated by recent experiments demonstrating surprising long-lived, periodic revivals after quantum quenches in Rydberg atom arrays, we introduce a manifold of locally entangled spin states, representable by low-bond dimension matrix product states, and derive equations of motion for them using the time-dependent variational principle. We find that they feature isolated, unstable periodic orbits, which capture the recurrences and represent nonergodic dynamical trajectories. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.040603DOI Listing
February 2019

Determination of the Pole Position of the Lightest Hybrid Meson Candidate.

Phys Rev Lett 2019 Feb;122(4):042002

Theory Center, Thomas Jefferson National Accelerator Facility, Newport News, VA 23606, USA.

Mapping states with explicit gluonic degrees of freedom in the light sector is a challenge, and has led to controversies in the past. In particular, the experiments have reported two different hybrid candidates with spin-exotic signature, π_{1}(1400) and π_{1}(1600), which couple separately to ηπ and η^{'}π. This picture is not compatible with recent Lattice QCD estimates for hybrid states, nor with most phenomenological models. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.042002DOI Listing
February 2019

Anomalous Collisions of Elastic Vector Solitons in Mechanical Metamaterials.

Phys Rev Lett 2019 Feb;122(4):044101

Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA.

We investigate via a combination of experiments and numerical analyses the collision of elastic vector solitons in a chain of rigid units connected by flexible hinges. Because of the vectorial nature of these solitons, very unusual behaviors are observed: while, as expected, the solitons emerge unaltered from the collision if they excite rotations of the same direction, they do not penetrate each other and instead repel one another if they induce rotations of the opposite direction. Our analysis reveals that such anomalous collisions are a consequence of the large-amplitude characteristics of the solitons, which locally modify the properties of the underlying media. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.044101DOI Listing
February 2019

Voyager 1 e^{±} Further Constrain Primordial Black Holes as Dark Matter.

Phys Rev Lett 2019 Feb;122(4):041104

Laboratoire de Physique Théorique et Hautes Energies (LPTHE), CNRS and Sorbonne Université, 4 Place Jussieu, Paris, France.

Primordial black holes (PBHs) with a mass M≲10^{17}  g are expected to inject sub-GeV electrons and positrons in the Galaxy via Hawking radiation. These cosmic rays are shielded by the solar magnetic field for Earth-bound detectors, but not for Voyager 1, which is now beyond the heliopause. We use its data to constrain the fraction of PBHs to the dark matter in the Galaxy, finding that PBHs with M<10^{16}  g cannot contribute more than 0. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.041104DOI Listing
February 2019

Flow-Arrest Transitions in Frictional Granular Matter.

Phys Rev Lett 2019 Feb;122(4):048003

Sandia National Laboratories, Albuquerque, New Mexico 87185, USA.

The transition between shear-flowing and shear-arrested states of frictional granular matter is studied using constant-stress discrete element simulations. By subjecting a dilute system of frictional grains to a constant external shear stress and pressure, friction-dependent critical shear stress and density are clearly identified with both exhibiting a crossover between low and high friction. The critical shear stress bifurcates two nonequilibrium steady states: (i) steady state shear flow characterized by a constant deformation rate, and (ii) shear arrest characterized by temporally decaying creep to a statically stable state. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.048003DOI Listing
February 2019
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Competing Universalities in Kardar-Parisi-Zhang Growth Models.

Phys Rev Lett 2019 Feb;122(4):040605

Institut für Biologische Physik, Universität zu Köln, Zülpicher Straße 77, 50937 Köln, Germany.

We report on the universality of height fluctuations at the crossing point of two interacting (1+1)-dimensional Kardar-Parisi-Zhang interfaces with curved and flat initial conditions. We introduce a control parameter p as the probability for the initially flat geometry to be chosen and compute the phase diagram as a function of p. We find that the distribution of the fluctuations converges to the Gaussian orthogonal ensemble Tracy-Widom distribution for p<0. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.040605DOI Listing
February 2019

Designer Spatial Control of Interactions in Ultracold Gases.

Phys Rev Lett 2019 Feb;122(4):040405

Department of Physics, North Carolina State University, Raleigh, North Carolina 27695, USA.

Designer optical control of interactions in ultracold atomic gases has wide applications, from creating new quantum phases to modeling the physics of black holes. We demonstrate wide tunability and spatial control of interactions in a two-component cloud of ^{6}Li fermions, using electromagnetically induced transparency. With two control fields detuned ≃1. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.040405DOI Listing
February 2019

Stark Many-Body Localization.

Phys Rev Lett 2019 Feb;122(4):040606

Physics Department, Technical University of Munich, James-Franck-Straße 1, 85748 Garching, Germany.

We consider spinless fermions on a finite one-dimensional lattice, interacting via nearest-neighbor repulsion and subject to a strong electric field. In the noninteracting case, due to Wannier-Stark localization, the single-particle wave functions are exponentially localized even though the model has no quenched disorder. We show that this system remains localized in the presence of interactions and exhibits physics analogous to models of conventional many-body localization (MBL). Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.040606DOI Listing
February 2019

Polaritonic Cross Feshbach Resonance.

Phys Rev Lett 2019 Feb;122(4):047402

Institute of Physics, School of Basic Sciences, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.

We demonstrate the existence of a cross Feshbach resonance by strongly driving a lower polariton mode and by monitoring in time the transmission of a short optical pulse at the energy of the upper polariton mode in a semiconductor microcavity. From the signatures of the optical resonance, strength, and sign of the energy shift, we attribute the origin of the scattering process between polariton modes with opposite circular polarization to a biexciton bound state. From this study, we infer the conditions required for a strong enhancement of the generation of entangled photon pairs. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.047402DOI Listing
February 2019

Exotic Vortex Lattices in Binary Repulsive Superfluids.

Phys Rev Lett 2019 Feb;122(4):045301

Department of Mathematics, Imperial College London, London SW7 2AZ, United Kingdom.

We investigate a mixture of two repulsively interacting superfluids with different constituent particle masses: m_{1}≠m_{2}. Solutions to the Gross-Pitaevskii equation for homogeneous infinite vortex lattices predict the existence of rich vortex lattice configurations, a number of which correspond to Platonic and Archimedean planar tilings. Some notable geometries include the snub-square, honeycomb, kagome, and herringbone lattice configurations. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.045301DOI Listing
February 2019

Production and Hadronic Decays of Higgs Bosons in Heavy-Ion Collisions.

Phys Rev Lett 2019 Feb;122(4):041803

Theoretical Physics Division, Institute of High Energy Physics, Chinese Academy of Science, Beijing 100049, China.

We examine Higgs boson production and decay in heavy-ion collisions at the LHC and future colliders. Owing to the long lifetime of the Higgs boson, its hadronic decays may experience little or no screening from the hot and dense quark-gluon plasma, whereas jets from hard scattering processes and from decays of the electroweak gauge bosons and the top quark suffer significant energy loss. This distinction can lead to enhanced signal to background ratios in hadronic decay channels and thus, for example, provide alternative ways to probe the Yukawa coupling of the Higgs boson to the bottom quark and its lifetime. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.041803DOI Listing
February 2019

Strong Quantum Nonlocality without Entanglement.

Phys Rev Lett 2019 Feb;122(4):040403

Department of Physics and Center for Astroparticle Physics and Space Science, Bose Institute, EN 80, Sector V, Bidhannagar, Kolkata 700091, India.

Quantum nonlocality is usually associated with entangled states by their violations of Bell-type inequalities. However, even unentangled systems, whose parts may have been prepared separately, can show nonlocal properties. In particular, a set of product states is said to exhibit "quantum nonlocality without entanglement" if the states are locally indistinguishable; i. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.040403DOI Listing
February 2019

Holographic Rényi Entropy at High Energy Density.

Authors:
Xi Dong

Phys Rev Lett 2019 Feb;122(4):041602

Department of Physics, University of California, Santa Barbara, California 93106, USA.

We show that Rényi entropies of subregions can be used to distinguish when the entire system is in a microcanonical ensemble from when it is in a canonical ensemble, at least in theories holographically dual to gravity. Simple expressions are provided for these Rényi entropies in a particular thermodynamic limit with high energy density and fixed fractional size of the subregion. Holographically, the Rényi entropies are determined by the areas of cosmic branes inserted into the bulk spacetime. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.041602DOI Listing
February 2019

Resonance Microwave Measurements of an Intrinsic Spin-Orbit Coupling Gap in Graphene: A Possible Indication of a Topological State.

Phys Rev Lett 2019 Feb;122(4):046403

Center for Hybrid Nanostructures (CHyN), University of Hamburg, Luruper Chaussee 149, 22607 Hamburg, Germany.

In 2005, Kane and Mele [Phys. Rev. Lett. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.046403DOI Listing
February 2019

Gravitational-Wave Fringes at LIGO: Detecting Compact Dark Matter by Gravitational Lensing.

Phys Rev Lett 2019 Feb;122(4):041103

Center for Theoretical Physics of the Universe, IBS, Daejeon 34051, Korea.

Utilizing gravitational-wave (GW) lensing opens a new way to understand the small-scale structure of the Universe. We show that, in spite of its coarse angular resolution and short duration of observation, LIGO can detect the GW lensing induced by small structures, in particular by compact dark matter (DM) or the primordial black hole of 10-10^{5}  M_{⊙}, which remains an interesting DM candidate. The lensing is detected through GW frequency chirping, creating the natural and rapid change of lensing patterns: frequency-dependent amplification and modulation of GW waveforms. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.041103DOI Listing
February 2019

Anderson Photon-Phonon Colocalization in Certain Random Superlattices.

Phys Rev Lett 2019 Feb;122(4):043903

Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain.

Fundamental observations in physics ranging from gravitational wave detection to laser cooling of a nanomechanical oscillator into its quantum ground state rely on the interaction between the optical and the mechanical degrees of freedom. A key parameter to engineer this interaction is the spatial overlap between the two fields, optimized in carefully designed resonators on a case-by-case basis. Disorder is an alternative strategy to confine light and sound at the nanoscale. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.043903DOI Listing
February 2019

Tracking Dark Excitons with Exciton Polaritons in Semiconductor Microcavities.

Phys Rev Lett 2019 Feb;122(4):047403

Experimentelle Physik 2, Technische Universität Dortmund, D-44221 Dortmund, Germany.

Dark excitons are of fundamental importance for a wide variety of processes in semiconductors but are difficult to investigate using optical techniques due to their weak interaction with light fields. We reveal and characterize dark excitons nonresonantly injected into a semiconductor microcavity structure containing InGaAs/GaAs quantum wells by a gated train of eight 100 fs pulses separated by 13 ns by monitoring their interactions with the bright lower polariton mode. We find a surprisingly long dark exciton lifetime of more than 20 ns, which is longer than the time delay between two consecutive pulses. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.047403DOI Listing
February 2019

Anomalous Low-Temperature Enhancement of Supercurrent in Topological-Insulator Nanoribbon Josephson Junctions: Evidence for Low-Energy Andreev Bound States.

Phys Rev Lett 2019 Feb;122(4):047003

School of Electrical and Computer Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA.

We report anomalous enhancement of the critical current at low temperatures in gate-tunable Josephson junctions made from topological insulator BiSbTeSe_{2} nanoribbons with superconducting Nb electrodes. In contrast to conventional junctions, as a function of the decreasing temperature T, the increasing critical current I_{c} exhibits a sharp upturn at a temperature T_{*} around 20% of the junction critical temperature for several different samples and various gate voltages. The I_{c} vs T demonstrates a short junction behavior for T>T_{*}, but crosses over to a long junction behavior for TRead More

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http://dx.doi.org/10.1103/PhysRevLett.122.047003DOI Listing
February 2019
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Unrestored Electroweak Symmetry.

Phys Rev Lett 2019 Feb;122(4):041802

Berkeley Center for Theoretical Physics, Department of Physics, University of California, Berkeley, California 94720, USA and Theoretical Physics Group, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.

The commonly assumed cosmological history of our Universe is that at early times and high temperatures the Universe went through an electroweak phase transition (EWPT). Assuming an EWPT, and depending on its strength, there are many implications for baryogenesis, gravitational waves, and the evolution of the Universe in general. However, it is not true that all spontaneously broken symmetries at zero temperature are restored at high temperature. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.041802DOI Listing
February 2019
2 Reads

Landauer's Erasure Principle in a Squeezed Thermal Memory.

Authors:
Jan Klaers

Phys Rev Lett 2019 Feb;122(4):040602

Complex Photonic Systems (COPS), MESA+ Institute for Nanotechnology, University of Twente, 7522 NB Enschede, Netherlands.

Landauer's erasure principle states that the irreversible erasure of a one-bit memory, embedded in a thermal environment, is accompanied with a work input of at least k_{B}Tln2. Fundamental to that principle is the assumption that the physical states representing the two possible logical states are close to thermal equilibrium. Here, we propose and theoretically analyze a minimalist mechanical model of a one-bit memory operating with squeezed thermal states. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.040602DOI Listing
February 2019

Out-of-Time-Ordered-Correlator Quasiprobabilities Robustly Witness Scrambling.

Phys Rev Lett 2019 Feb;122(4):040404

Schmid College of Science and Technology, Chapman University, Orange, California 92866, USA.

Out-of-time-ordered correlators (OTOCs) have received considerable recent attention as qualitative witnesses of information scrambling in many-body quantum systems. Theoretical discussions of OTOCs typically focus on closed systems, raising the question of their suitability as scrambling witnesses in realistic open systems. We demonstrate empirically that the nonclassical negativity of the quasiprobability distribution (QPD) behind the OTOC is a more sensitive witness for scrambling than the OTOC itself. Read More

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https://link.aps.org/doi/10.1103/PhysRevLett.122.040404
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http://dx.doi.org/10.1103/PhysRevLett.122.040404DOI Listing
February 2019
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Large Impact of the Decay of Niobium Isomers on the Reactor ν[over ¯]_{e} Summation Calculations.

Phys Rev Lett 2019 Feb;122(4):042502

Subatech, IMT-Atlantique, Université de Nantes, CNRS-IN2P3, F-44307 Nantes, France.

Even mass neutron-rich niobium isotopes are among the principal contributors to the reactor antineutrino energy spectrum. They are also among the most challenging to measure due to the refractory nature of niobium, and because they exhibit isomeric states lying very close in energy. The β-intensity distributions of ^{100gs,100m}Nb and ^{102gs,102m}Nb β decays have been determined using the total absorption γ-ray spectroscopy technique. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.042502DOI Listing
February 2019

Fluorescence Spectrum and Thermalization in a Driven Coupled Cavity Array.

Phys Rev Lett 2019 Feb;122(4):043602

SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, United Kingdom.

We calculate the fluorescence spectra of a driven lattice of coupled cavities. To do this, we extend methods of evaluating two-time correlations in infinite lattices to open quantum systems; this allows access to momentum-resolved fluorescence spectrum. We illustrate this for a driven-dissipative transverse-field anisotropic XY model. Read More

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http://dx.doi.org/10.1103/PhysRevLett.122.043602DOI Listing
February 2019

Role of Electric Fields on Enhanced Electron Correlation in Surface-Doped FeSe.

Phys Rev Lett 2019 Feb;122(4):046401

Department of Physics, Yonsei University, Seoul 03722, Republic of Korea.

Electron-doped high-T_{c} FeSe reportedly has a strong electron correlation that is enhanced with doping. It has been noticed that significant electric fields exist inevitably between FeSe and external donors along with electron transfer. However, the effects of such fields on the electron correlation are yet to be explored. Read More

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February 2019

Energy-Ratio-Based Measure of Elastic Anisotropy.

Phys Rev Lett 2019 Feb;122(4):045502

School of Engineering, Brown University, Providence, Rhode Island 02912, USA.

Many materials are anisotropic. However, there is no widely accepted measure for characterizing the degree of elastic anisotropy. Here, assuming that the limiting case of extreme anisotropy should possess a positive semidefinite stiffness matrix, we propose three criteria to evaluate measures of anisotropy and show that the existing measures in the literature do not satisfy all of the proposed criteria. Read More

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February 2019

Chiral Interactions up to Next-to-Next-to-Next-to-Leading Order and Nuclear Saturation.

Phys Rev Lett 2019 Feb;122(4):042501

Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany.

We present an efficient Monte Carlo framework for perturbative calculations of infinite nuclear matter based on chiral two-, three-, and four-nucleon interactions. The method enables the incorporation of all many-body contributions in a straightforward and transparent way, and makes it possible to extract systematic uncertainty estimates by performing order-by-order calculations in the chiral expansion as well as the many-body expansion. The versatility of this new framework is demonstrated by applying it to chiral low-momentum interactions, exhibiting a very good many-body convergence up to fourth order. Read More

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February 2019

Towards Understanding the Origin of Cosmic-Ray Positrons.

Authors:
M Aguilar L Ali Cavasonza G Ambrosi L Arruda N Attig P Azzarello A Bachlechner F Barao A Barrau L Barrin A Bartoloni L Basara S Başeğmez-du Pree R Battiston U Becker M Behlmann B Beischer J Berdugo B Bertucci V Bindi W de Boer K Bollweg B Borgia M J Boschini M Bourquin E F Bueno J Burger W J Burger X D Cai M Capell S Caroff J Casaus G Castellini F Cervelli Y H Chang G M Chen H S Chen Y Chen L Cheng H Y Chou V Choutko C H Chung C Clark G Coignet C Consolandi A Contin C Corti M Crispoltoni Z Cui K Dadzie Y M Dai A Datta C Delgado S Della Torre M B Demirköz L Derome S Di Falco F Dimiccoli C Díaz P von Doetinchem F Dong F Donnini M Duranti A Egorov A Eline T Eronen J Feng E Fiandrini P Fisher V Formato Y Galaktionov R J García-López C Gargiulo H Gast I Gebauer M Gervasi F Giovacchini D M Gómez-Coral J Gong C Goy V Grabski D Grandi M Graziani K H Guo S Haino K C Han Z H He M Heil T H Hsieh H Huang Z C Huang M Incagli Yi Jia H Jinchi K Kanishev B Khiali Th Kirn C Konak O Kounina A Kounine V Koutsenko A Kulemzin G La Vacca E Laudi G Laurenti I Lazzizzera A Lebedev H T Lee S C Lee C Leluc J Q Li Q Li T X Li Z H Li C Light C H Lin T Lippert F Z Liu Hu Liu Z Liu S Q Lu Y S Lu K Luebelsmeyer F Luo J Z Luo Xi Luo S S Lyu F Machate C Mañá J Marín T Martin G Martínez N Masi D Maurin A Menchaca-Rocha Q Meng D C Mo M Molero P Mott L Mussolin T Nelson J Q Ni N Nikonov F Nozzoli A Oliva M Orcinha M Palermo F Palmonari M Paniccia A Pashnin M Pauluzzi S Pensotti C Perrina H D Phan N Picot-Clemente V Plyaskin M Pohl V Poireau A Popkow L Quadrani X M Qi X Qin Z Y Qu P G Rancoita D Rapin A Reina Conde S Rosier-Lees A Rozhkov D Rozza R Sagdeev C Solano S Schael S M Schmidt A Schulz von Dratzig G Schwering E S Seo B S Shan J Y Shi T Siedenburg J W Song Z T Sun M Tacconi X W Tang Z C Tang J Tian Samuel C C Ting S M Ting N Tomassetti J Torsti T Urban V Vagelli E Valente E Valtonen M Vázquez Acosta M Vecchi M Velasco J P Vialle J Vizán L Q Wang N H Wang Q L Wang X Wang X Q Wang Z X Wang J Wei Z L Weng H Wu R Q Xiong W Xu Q Yan Y Yang H Yi Y J Yu Z Q Yu M Zannoni S Zeissler C Zhang F Zhang J H Zhang Z Zhang F Zhao Z M Zheng H L Zhuang V Zhukov A Zichichi N Zimmermann P Zuccon

Phys Rev Lett 2019 Feb;122(4):041102

INFN TIFPA, I-38123 Povo, Trento, Italy.

Precision measurements of cosmic ray positrons are presented up to 1 TeV based on 1.9 million positrons collected by the Alpha Magnetic Spectrometer on the International Space Station. The positron flux exhibits complex energy dependence. Read More

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February 2019

Racemic Amino Acid Piezoelectric Transducer.

Phys Rev Lett 2019 Feb;122(4):047701

Department of Physics, University of Limerick, Limerick V94 T9PX, Ireland.

Single crystal L-amino acids can exhibit technologically useful piezoelectric and nonlinear optical properties. Here we predict, using density functional theory, the piezoelectric charge and strain and voltage tensors of the racemic amino acid DL alanine, and use the modeling data to guide the first macroscopic and nanoscopic piezoelectric measurements on DL-alanine single crystals and polycrystalline aggregates. We demonstrate voltage generation of up to 0. Read More

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February 2019
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Observation of Transverse Λ/Λ[over ¯] Hyperon Polarization in e^{+}e^{-} Annihilation at Belle.

Authors:
Y Guan A Vossen I Adachi K Adamczyk J K Ahn H Aihara S Al Said D M Asner H Atmacan V Aulchenko T Aushev R Ayad V Babu I Badhrees A M Bakich V Bansal P Behera C Beleño M Berger V Bhardwaj B Bhuyan T Bilka J Biswal A Bobrov G Bonvicini A Bozek M Bračko T E Browder L Cao D Červenkov P Chang V Chekelian A Chen B G Cheon K Chilikin K Cho S-K Choi Y Choi D Cinabro S Cunliffe N Dash S Di Carlo J Dingfelder Z Doležal T V Dong Z Drásal S Eidelman D Epifanov J E Fast T Ferber B G Fulsom R Garg V Gaur N Gabyshev A Garmash M Gelb A Giri P Goldenzweig B Golob E Guido J Haba K Hayasaka H Hayashii S Hirose W-S Hou T Iijima K Inami G Inguglia A Ishikawa R Itoh M Iwasaki Y Iwasaki W W Jacobs I Jaegle H B Jeon S Jia Y Jin D Joffe K K Joo T Julius K H Kang T Kawasaki C Kiesling D Y Kim H J Kim J B Kim K T Kim S H Kim K Kinoshita P Kodyš S Korpar D Kotchetkov P Križan R Kroeger P Krokovny T Kuhr R Kulasiri A Kuzmin Y-J Kwon J S Lange I S Lee S C Lee L K Li Y B Li L Li Gioi J Libby D Liventsev M Lubej T Luo M Masuda T Matsuda D Matvienko M Merola H Miyata R Mizuk G B Mohanty H K Moon T Mori R Mussa M Nakao T Nanut K J Nath Z Natkaniec M Nayak M Niiyama N K Nisar S Nishida S Ogawa S Okuno H Ono P Pakhlov G Pakhlova B Pal S Pardi H Park S Paul T K Pedlar R Pestotnik L E Piilonen V Popov E Prencipe A Rabusov A Rostomyan G Russo D Sahoo Y Sakai M Salehi S Sandilya L Santelj T Sanuki V Savinov O Schneider G Schnell C Schwanda R Seidl Y Seino K Senyo O Seon M E Sevior V Shebalin C P Shen T-A Shibata J-G Shiu F Simon A Sokolov E Solovieva M Starič J F Strube M Sumihama T Sumiyoshi W Sutcliffe K Suzuki M Takizawa U Tamponi K Tanida F Tenchini M Uchida T Uglov Y Unno S Uno P Urquijo Y Usov S E Vahsen C Van Hulse R Van Tonder G Varner A Vinokurova V Vorobyev E Waheed B Wang C H Wang M-Z Wang P Wang X L Wang S Watanuki E Widmann E Won H Ye J Yelton J H Yin C Z Yuan Y Yusa Z P Zhang V Zhilich V Zhukova V Zhulanov A Zupanc

Phys Rev Lett 2019 Feb;122(4):042001

J. Stefan Institute, 1000 Ljubljana.

We report the first observation of the spontaneous polarization of Λ and Λ[over ¯] hyperons transverse to the production plane in e^{+}e^{-} annihilation, which is attributed to the effect arising from a polarizing fragmentation function. For inclusive Λ/Λ[over ¯] production, we also report results with subtracted feed-down contributions from Σ^{0} and charm. This measurement uses a dataset of 800. Read More

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February 2019
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Unified View of Nonlinear Wave Structures Associated with Whistler-Mode Chorus.

Phys Rev Lett 2019 Feb;122(4):045101

Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242, USA.

A range of nonlinear wave structures, including Langmuir waves, unipolar electric fields, and bipolar electric fields, are often observed in association with whistler-mode chorus waves in near-Earth space. We demonstrate that the three seemingly different nonlinear wave structures originate from the same nonlinear electron trapping process by whistler-mode chorus waves. The ratio of the Landau resonant velocity to the electron thermal velocity controls the type of nonlinear wave structures that will be generated. Read More

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February 2019

Puzzle of Complete Fusion Suppression in Weakly Bound Nuclei: A Trojan Horse Effect?

Phys Rev Lett 2019 Feb;122(4):042503

Departamento de FAMN, Universidad de Sevilla, Apartado 1065, 41080 Sevilla, Spain.

Experimental studies of nuclear collisions involving light weakly bound nuclei show a systematic suppression of the complete fusion cross section by ∼30% with respect to the expectation for tightly bound nuclei, at energies above the Coulomb barrier. Although it is widely accepted that the phenomenon is related to the weak binding of these nuclei, the origin of this suppression is not fully understood. Here, we present a novel approach that provides the complete fusion for weakly bound nuclei and relates its suppression to the competition between the different mechanisms contributing to the reaction cross section. Read More

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February 2019

Direct Transfer of Light's Orbital Angular Momentum onto a Nonresonantly Excited Polariton Superfluid.

Phys Rev Lett 2019 Feb;122(4):045302

Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.

Recently, exciton polaritons in a semiconductor microcavity were found to condense into a coherent ground state much like a Bose-Einstein condensate and a superfluid. They have become a unique testbed for generating and manipulating quantum vortices in a driven-dissipative superfluid. Here, we generate an exciton-polariton condensate with a nonresonant Laguerre-Gaussian optical beam and verify the direct transfer of light's orbital angular momentum to an exciton-polariton quantum fluid. Read More

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February 2019
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Direct Measurement of Length Scale Dependence of the Hydrophobic Free Energy of a Single Collapsed Polymer Nanosphere.

Phys Rev Lett 2019 Feb;122(4):047801

Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructure, Department of Physics, Nanjing University, Nanjing 210093, People's Republic of China.

The physics underlying hydrophobicity at macroscopic and microscopic levels is fundamentally distinct. However, experimentally quantifying the length scale dependence of hydrophobicity is challenging. Here we show that the size-dependent hydrophobic free energy of a collapsed polymer nanosphere can be continuously monitored from its single-molecule force-extension curve using a novel theoretical framework. Read More

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February 2019

Emergence of Active Nematic Behavior in Monolayers of Isotropic Cells.

Phys Rev Lett 2019 Feb;122(4):048004

The Rudolf Peierls Centre for Theoretical Physics, Clarendon Laboratory, Parks Road, University of Oxford, Oxford OX1 3PU, United Kingdom.

There is now growing evidence of the emergence and biological functionality of liquid crystal features, including nematic order and topological defects, in cellular tissues. However, how such features that intrinsically rely on particle elongation emerge in monolayers of cells with isotropic shapes is an outstanding question. In this Letter, we present a minimal model of cellular monolayers based on cell deformation and force transmission at the cell-cell interface that explains the formation of topological defects and captures the flow-field and stress patterns around them. Read More

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February 2019