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PubMed Journal Database | Physical review letters RSS

21:28 EST 12th November 2018 | BioPortfolio

The US National Library of Medicine and National Institutes of Health manage PubMed.gov which comprises of more than 21 million records, papers, reports for biomedical literature, including MEDLINE, life science and medical journals, articles, reviews, reports and  books.  BioPortfolio aims to publish relevant information on published papers, clinical trials and news associated with users selected topics.

For example view all recent relevant publications on Epigenetics and associated publications and clincial trials.

Showing PubMed Articles 1–25 of 5,200+ from Physical review letters

Signature of the s-Wave Regime High above Ultralow Temperatures.

Resonant exchange is a general process playing a key role in many-body dynamics and transport phenomena, such as spin, charge, or excitation diffusion. The underlying process is described by the resonant exchange cross section. We show that the s-wave scattering, generally thought to contribute mainly in the ultracold (or Wigner) regime, dictates the overall cross section over a broad range of energies. We derive an analytical expression and explain its applicability high above the Wigner regime. In particu...

Search for CP Violation in Neutrino and Antineutrino Oscillations by the T2K Experiment with 2.2×10^{21} Protons on Target.

The T2K experiment measures muon neutrino disappearance and electron neutrino appearance in accelerator-produced neutrino and antineutrino beams. With an exposure of 14.7(7.6)×10^{20} protons on target in the neutrino (antineutrino) mode, 89 ν_{e} candidates and seven anti-ν_{e} candidates are observed, while 67.5 and 9.0 are expected for δ_{CP}=0 and normal mass ordering. The obtained 2σ confidence interval for the CP-violating phase, δ_{CP}, does not include the CP-conserving cases (δ_{CP}=0, π). ...

Recovering Quantum Gates from Few Average Gate Fidelities.

Characterizing quantum processes is a key task in the development of quantum technologies, especially at the noisy intermediate scale of today's devices. One method for characterizing processes is randomized benchmarking, which is robust against state preparation and measurement errors and can be used to benchmark Clifford gates. Compressed sensing techniques achieve full tomography of quantum channels essentially at optimal resource efficiency. In this Letter, we show that the favorable features of both ap...

Detection of a Disorder-Induced Bose-Einstein Condensate in a Quantum Spin Material at High Magnetic Fields.

The coupled spin-1 chains material NiCl_{2}-4SC(NH_{2})_{2} (DTN) doped with Br impurities is expected to be a perfect candidate for observing many-body localization at high magnetic field: the so-called "Bose glass," a zero-temperature bosonic fluid, compressible, gapless, incoherent, and short-range correlated. Using nuclear magnetic resonance, we critically address the stability of the Bose glass in doped DTN, and find that it hosts a novel disorder-induced ordered state of matter, where many-body physic...

General Relativity from Scattering Amplitudes.

Weoutline the program to apply modern quantum field theory methods to calculate observables in classical general relativity through a truncation to classical terms of the multigraviton, two-body, on-shell scattering amplitudes between massive fields. Since only long-distance interactions corresponding to nonanalytic pieces need to be included, unitarity cuts provide substantial simplifications for both post-Newtonian and post-Minkowskian expansions. We illustrate this quantum field theoretic approach to cla...

Nonlinear Kinetic Ion Response to Small Scale Magnetic Islands in Tokamak Plasmas: Neoclassical Tearing Mode Threshold Physics.

A new drift-kinetic theory of the ion response to magnetic islands in tokamak plasmas is presented. Small islands are considered, with widths w much smaller than the plasma radius r, but comparable to the trapped ion orbit width ρ_{bi}. An expansion in w/r reduces the system dimensions from five down to four. In the absence of an electrostatic potential, the ions follow stream lines that map out a drift-island structure that is identical to the magnetic island, but shifted by an amount ∼ few ρ_{bi}. The...

Strong Purcell Effect on a Neutral Atom Trapped in an Open Fiber Cavity.

We observe a sixfold Purcell broadening of the D_{2} line of an optically trapped ^{87}Rb atom strongly coupled to a fiber cavity. Under external illumination by a near-resonant laser, up to 90% of the atom's fluorescence is emitted into the resonant cavity mode. The sub-Poissonian statistics of the cavity output and the Purcell enhancement of the atomic decay rate are confirmed by the observation of a strongly narrowed antibunching dip in the photon autocorrelation function. The photon leakage through the ...

Measurement of the Branching Fraction For the Semileptonic Decay D^{0(+)}→π^{-(0)}μ^{+}ν_{μ} and Test of Lepton Flavor Universality.

Using a data sample corresponding to an integrated luminosity of 2.93  fb^{-1} taken at a center-of-mass energy of 3.773 GeV with the BESIII detector operated at the BEPCII collider, we perform an analysis of the semileptonic decays D^{0(+)}→π^{-(0)}μ^{+}ν_{μ}. The branching fractions of D^{0}→π^{-}μ^{+}ν_{μ} and D^{+}→π^{0}μ^{+}ν_{μ} are measured to be (0.272±0.008_{stat}±0.006_{syst})% and (0.350±0.011_{stat}±0.010_{syst})%, respectively, where the former is of much improved pre...

Precision Test of AdS_{6}/CFT_{5} in Type IIB String Theory.

Superconformal field theories (SCFTs) in dimensions greater than 4 have become an integral part in the general understanding of quantum field theory, with many interesting implications in lower dimensions. They are hard to define using traditional methods, but can be engineered in string theory. Recently, a large class of AdS/CFT dualities has been constructed for five-dimensional SCFTs, which further supports their existence and allows for quantitative studies. We confront these dualities with a decisive t...

Second-Harmonic Current-Phase Relation in Josephson Junctions with Ferromagnetic Barriers.

We report the observation of a current-phase relation dominated by the second Josephson harmonic in superconductor-ferromagnet-superconductor junctions. The exotic current-phase relation is realized in the vicinity of a temperature-controlled 0-to-π junction transition, at which the first Josephson harmonic vanishes. Direct current-phase relation measurements, as well as Josephson interferometry, nonvanishing supercurrent and half-integer Shapiro steps at the 0-π transition self-consistently point to an i...

Symmetry Protection of Photonic Entanglement in the Interaction with a Single Nanoaperture.

In this work, we experimentally show that quantum entanglement can be symmetry protected in the interaction with a single subwavelength plasmonic nanoaperture, with a total volume of V∼0.2λ^{3}. In particular, we experimentally demonstrate that two-photon entanglement can be either completely preserved or completely lost after the interaction with the nanoaperture, solely depending on the relative phase between the quantum states. We achieve this effect by using specially engineered two-photon states to ...

Fermi Surface Nesting and Phonon Frequency Gap Drive Anomalous Thermal Transport.

The lattice thermal conductivity, k_{L}, of typical metallic and nonmetallic crystals decreases rapidly with increasing temperature because phonons interact more strongly with other phonons than they do with electrons. Using first principles calculations, we show that k_{L} can become nearly independent of temperature in metals that have nested Fermi surfaces and large frequency gaps between acoustic and optic phonons. Then, the interactions between phonons and electrons become much stronger than the mutual...

Separating Dipole and Quadrupole Contributions to Single-Photon Double Ionization.

We report on a kinematically complete measurement of double ionization of helium by a single 1100 eV circularly polarized photon. By exploiting dipole selection rules in the two-electron continuum state, we observed the angular emission pattern of electrons originating from a pure quadrupole transition. Our fully differential experimental data and companion ab initio nonperturbative theory show the separation of dipole and quadrupole contributions to photo-double-ionization and provide new insight into th...

Demonstration of Einstein-Podolsky-Rosen Steering Using Hybrid Continuous- and Discrete-Variable Entanglement of Light.

Einstein-Podolsky-Rosen steering is known to be a key resource for one-sided device-independent quantum information protocols. Here we demonstrate steering using hybrid entanglement between continuous- and discrete-variable optical qubits. To this end, we report on suitable steering inequalities and detail the implementation and requirements for this demonstration. Steering is experimentally certified by observing a violation by more than 5 standard deviations. Our results illustrate the potential of optica...

Focusing of High-Brightness Electron Beams with Active-Plasma Lenses.

Plasma-based technology promises a tremendous reduction in size of accelerators used for research, medical, and industrial applications, making it possible to develop tabletop machines accessible for a broader scientific community. By overcoming current limits of conventional accelerators and pushing particles to larger and larger energies, the availability of strong and tunable focusing optics is mandatory also because plasma-accelerated beams usually have large angular divergences. In this regard, active-...

Observation of Subradiant Atomic Momentum States with Bose-Einstein Condensates in a Recoil Resolving Optical Ring Resonator.

We experimentally investigate the formation of subradiant atomic momentum states in Bose-Einstein condensates inside a recoil resolving optical ring resonator according to the theoretical proposal of Cola, Bigerni, and Piovella. The atoms are pumped from the side with laser light that contains two frequency components. They resonantly drive cavity assisted Raman transitions between three discreet atomic momentum states. Within a few hundred microseconds, the system evolves into a stationary subradiant state...

Particle Collisions and Negative Nonlocal Response of Ballistic Electrons.

An electric field that builds in the direction against current, known as negative nonlocal resistance, arises naturally in viscous flows and is thus often taken as a telltale of this regime. Here, we predict negative resistance for the ballistic regime, wherein the ee collision mean free path is greater than the length scale at which the system is being probed. Therefore, negative resistance alone does not provide strong evidence for the occurrence of the hydrodynamic regime; it must thus be demoted from th...

Jerk Current: A Novel Bulk Photovoltaic Effect.

We investigate a physical divergence of the third order polarization susceptibility representing a photoinduced current in biased crystalline insulators. This current grows quadratically with illumination time in the absence of momentum relaxation and saturation; we refer to it as the jerk current. Two contributions to the current are identified. The first is a hydrodynamic acceleration of optically injected carriers by the static electric field, and the second is the change in the carrier injection rate in...

Dynamo Effect and Turbulence in Hydrodynamic Weyl Metals.

The dynamo effect is a class of macroscopic phenomena responsible for generating and maintaining magnetic fields in astrophysical bodies. It hinges on the hydrodynamic three-dimensional motion of conducting gases and plasmas that achieve high hydrodynamic and/or magnetic Reynolds numbers due to the large length scales involved. The existing laboratory experiments modeling dynamos are challenging and involve large apparatuses containing conducting fluids subject to fast helical flows. Here we propose that el...

Engineering Carrier Effective Masses in Ultrathin Quantum Wells of IrO_{2}.

The carrier effective mass plays a crucial role in modern electronic, optical, and catalytic devices and is fundamentally related to key properties of solids such as the mobility and density of states. Here we demonstrate a method to deterministically engineer the effective mass using spatial confinement in metallic quantum wells of the transition metal oxide IrO_{2}. Using a combination of in situ angle-resolved photoemission spectroscopy measurements in conjunction with precise synthesis by oxide molecul...

Attosecond Control of Restoration of Electronic Structure Symmetry.

Laser pulses can break the electronic structure symmetry of atoms and molecules by preparing a superposition of states with different irreducible representations. Here, we discover the reverse process, symmetry restoration, by means of two circularly polarized laser pulses. The laser pulse for symmetry restoration is designed as a copy of the pulse for symmetry breaking. Symmetry restoration is achieved if the time delay is chosen such that the superposed states have the same phases at the temporal center. ...

Heavy Physics Contributions to Neutrinoless Double Beta Decay from QCD.

Observation of neutrinoless double beta decay, a lepton number violating process that has been proposed to clarify the nature of neutrino masses, has spawned an enormous world-wide experimental effort. Relating nuclear decay rates to high-energy, beyond the standard model (BSM) physics requires detailed knowledge of nonperturbative QCD effects. Using lattice QCD, we compute the necessary matrix elements of short-range operators, which arise due to heavy BSM mediators, that contribute to this decay via the l...

Enhancement of Microorganism Swimming Speed in Active Matter.

We study a swimming undulating sheet in the isotropic phase of an active nematic liquid crystal. Activity changes the effective shear viscosity, reducing it to zero at a critical value of activity. Expanding in the sheet amplitude, we find that the correction to the swimming speed due to activity is inversely proportional to the effective shear viscosity. Our perturbative calculation becomes invalid near the critical value of activity; using numerical methods to probe this regime, we find that activity enha...

Finite-Temperature Equation of State of Polarized Fermions at Unitarity.

We study in a nonperturbative fashion the thermodynamics of a unitary Fermi gas over a wide range of temperatures and spin polarizations. To this end, we use the complex Langevin method, a first principles approach for strongly coupled systems. Specifically, we show results for the density equation of state, the magnetization, and the magnetic susceptibility. At zero polarization, our results agree well with state-of-the-art results for the density equation of state and with experimental data. At finite pol...

Topology and Geometry of Spin Origami.

Kagome antiferromagnets are known to be highly frustrated and degenerate when they possess simple, isotropic interactions. We consider the entire class of these magnets when their interactions are spatially anisotropic. We do so by identifying a certain class of systems whose degenerate ground states can be mapped onto the folding motions of a generalized "spin origami" two-dimensional mechanical sheet. Some such anisotropic spin systems, including Cs_{2}ZrCu_{3}F_{12}, map onto flat origami sheets, possess...


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