We introduce a new class of nondiffracting optical pulses possessing orbital angular momentum. By generalizing the $X$-wave solution of the Maxwell equation, we discover the coupling between angular momentum and the temporal degrees of freedom of ultrashort pulses. The spatial twist of propagation inv…

[Phys. Rev. Lett. 115, 100401] Published Tue Sep 01, 2015

]]>The collective excitations of a quantum many-body system of trapped ions is characterized in a new spectroscopic technique that probes the eigenmodes of the system. The technique allows the excited quasiparticles to be individually manipulated and measured.

[Phys. Rev. Lett. 115, 100501] Published Tue Sep 01, 2015

]]>We present a new test of the validity of the Friedmann-Lemaître-Robertson-Walker (FLRW) metric, based on comparing the distance from redshift 0 to ${z}_{1}$ and from ${z}_{1}$ to ${z}_{2}$ to the distance from 0 to ${z}_{2}$. If the Universe is described by the FLRW metric, the comparison provides a model-independent measureme…

[Phys. Rev. Lett. 115, 101301] Published Tue Sep 01, 2015

]]>Differential cross sections of isoscalar and isovector spin-$M1$ (${0}^{+}\to {1}^{+}$) transitions are measured using high-energy-resolution proton inelastic scattering at ${E}_{p}=295\text{\hspace{0.17em}}\text{\hspace{0.17em}}\mathrm{MeV}$ on ${}^{24}\mathrm{Mg}$, ${}^{28}\mathrm{Si}$, ${}^{32}\mathrm{S}$, and ${}^{36}\mathrm{Ar}$ at 0°–14°. The squared spin-$M1$ nuclear transition matrix elements are deduced from the measured differe…

[Phys. Rev. Lett. 115, 102501] Published Tue Sep 01, 2015

]]>We show that dynamic exchange is a dominant effect in strong field ionization of molecules. In ${\mathrm{CO}}_{2}$ it fixes the peak ionization yield at the experimentally observed angle of 45° between polarization direction and the molecular axis. For ${\mathrm{O}}_{2}$ it changes the angle of peak emission and for ${\mathrm{N}}_{2}$ the alignme…

[Phys. Rev. Lett. 115, 103002] Published Tue Sep 01, 2015

]]>Broadband atmospheric phase spectra are acquired with a phase-sensitive dual-frequency-comb spectrometer by implementing adaptive compensation for the strong decoherence from atmospheric turbulence. The compensation is possible due to the pistonlike behavior of turbulence across a single spatial-mod…

[Phys. Rev. Lett. 115, 103901] Published Tue Sep 01, 2015

]]>We present the first experimental observation of resonance-assisted tunneling, a wave phenomenon, where regular-to-chaotic tunneling is strongly enhanced by the presence of a classical nonlinear resonance chain. For this we use a microwave cavity made of oxygen free copper with the shape of a desymm…

[Phys. Rev. Lett. 115, 104101] Published Tue Sep 01, 2015

]]>A conceptual mechanism of amplification of phonons by phonons on the basis of a nonlinear band-gap transmission (supratransmission) phenomenon is presented. As an example, a system of weakly coupled chains of anharmonic oscillators is considered. One (source) chain is driven harmonically by a bounda…

[Phys. Rev. Lett. 115, 104301] Published Tue Sep 01, 2015

]]>The electronic structure and phase stability of paramagnetic FeSe is computed by using a combination of *ab initio* methods for calculating band structure and dynamical mean-field theory. Our results reveal a topological change (Lifshitz transition) of the Fermi surface upon a moderate expansion of th…

[Phys. Rev. Lett. 115, 106402] Published Tue Sep 01, 2015

]]>We perform, as a function of uniaxial stress, an optical-reflectivity investigation of the representative “parent” ferropnictide ${\mathrm{BaFe}}_{2}{\mathrm{As}}_{2}$ in a broad spectral range, across the tetragonal-to-orthorhombic phase transition and the onset of the long-range antiferromagnetic (AFM) order. The infrared resp…

[Phys. Rev. Lett. 115, 107001] Published Tue Sep 01, 2015

]]>We demonstrate that frustrated exchange interactions can produce exotic 3D crystals of vortex strings near the saturation field ($H={H}_{\mathrm{sat}}$) of body- and face-centered cubic Mott insulators. The combination of cubic symmetry and frustration leads to a magnon spectrum of the fully polarized spin state ($H\dots $

[Phys. Rev. Lett. 115, 107201] Published Tue Sep 01, 2015

]]>The mechanisms of cold and pressure denaturation of proteins are matter of debate and are commonly understood as due to water-mediated interactions. Here, we study several cases of proteins, with or without a unique native state, with or without hydrophilic residues, by means of a coarse-grain prote…

[Phys. Rev. Lett. 115, 108101] Published Tue Sep 01, 2015

]]>We demonstrate light-pulse atom interferometry with large-momentum-transfer atom optics based on stimulated Raman transitions and frequency-swept adiabatic rapid passage. Our atom optics have produced momentum splittings of up to 30 photon recoil momenta in an acceleration-sensitive interferometer f…

[Phys. Rev. Lett. 115, 103001] Published Mon Aug 31, 2015

]]>Ceramics are strong, but their low fracture toughness prevents extended engineering applications. In particular, boron carbide (${\mathrm{B}}_{4}\mathrm{C}$), the third hardest material in nature, has not been incorporated into many commercial applications because it exhibits anomalous failure when subjected to hypervelocit…

[Phys. Rev. Lett. 115, 105501] Published Mon Aug 31, 2015

]]>Using first-principles calculations, we determined the epitaxial-strain dependence of the ground state of the $1:1$ ${\mathrm{SrCrO}}_{3}/{\mathrm{SrTiO}}_{3}$ superlattice. The superlattice layering leads to significant changes in the electronic states near the Fermi level, derived from Cr ${t}_{2g}$ orbitals. An insulating phase is fou…

[Phys. Rev. Lett. 115, 106401] Published Mon Aug 31, 2015

]]>Graphene subjected to *chiral*-symmetric disorder is believed to host zero energy modes (ZEMs) resilient to localization, as suggested by the renormalization group analysis of the underlying nonlinear sigma model. We report accurate quantum transport calculations in honeycomb lattices with in excess o…

[Phys. Rev. Lett. 115, 106601] Published Mon Aug 31, 2015

]]>Singlet excitons in $\pi $-stacked molecular crystals can split into two triplet excitons in a process called singlet fission that opens a route to carrier multiplication in photovoltaics. To resolve controversies about the mechanism of singlet fission, we have developed a first principles nonadiabatic q…

[Phys. Rev. Lett. 115, 107401] Published Mon Aug 31, 2015

]]>A long-standing problem in quantum mechanics is the minimum number of observables required for the characterization of unknown pure quantum states. The solution to this problem is especially important for the developing field of high-dimensional quantum information processing. In this work we demons…

[Phys. Rev. Lett. 115, 090401] Published Fri Aug 28, 2015

]]>Zero-point quantum fluctuations of the electromagnetic vacuum create the widely known London–van der Waals attractive force between two atoms. Recently, there has been a revived interest in the interaction of rotating matter with the quantum vacuum. Here, we consider a rotating pair of atoms maintai…

[Phys. Rev. Lett. 115, 090402] Published Fri Aug 28, 2015

]]>We derive a simple set of nonlinear, $(1+1)$-dimensional partial differential equations that describe the dynamical evolution of black strings and branes to leading order in the expansion in the inverse of the number of dimensions $D$. These equations are easily solved numerically. Their solution shows …

[Phys. Rev. Lett. 115, 091102] Published Fri Aug 28, 2015

]]>We have searched for periodic variations of the electronic recoil event rate in the (2–6) keV energy range recorded between February 2011 and March 2012 with the XENON100 detector, adding up to 224.6 live days in total. Following a detailed study to establish the stability of the detector and its ba…

[Phys. Rev. Lett. 115, 091302] Published Fri Aug 28, 2015

]]>We present a determination of the pion-nucleon ($\pi N$) $\sigma $ term ${\sigma}_{\pi N}$ based on the Cheng-Dashen low-energy theorem (LET), taking advantage of the recent high-precision data from pionic atoms to pin down the $\pi N$ scattering lengths as well as of constraints from analyticity, unitarity, and crossing symmetry i…

[Phys. Rev. Lett. 115, 092301] Published Fri Aug 28, 2015

]]>We present a mechanism of global reaction coordinate switching, namely, a phenomenon in which the reaction coordinate dynamically switches to another coordinate as the total energy of the system increases. The mechanism is based on global changes in the underlying phase space geometry caused by a sw…

[Phys. Rev. Lett. 115, 093003] Published Fri Aug 28, 2015

]]>The charge transfer (ionization) of hydrogen Rydberg atoms ($n=25\u201334$) incident on a Cu(100) surface is investigated. Unlike fully metallic surfaces, where the Rydberg electron energy is degenerate with the conduction band of the metal, the Cu(100) surface has a projected band gap at these energies, a…

[Phys. Rev. Lett. 115, 093201] Published Fri Aug 28, 2015

]]>We report on reproducible shock acceleration from irradiation of a $\lambda =10\text{\hspace{0.17em}}\text{\hspace{0.17em}}\mu \mathrm{m}$ ${\mathrm{CO}}_{2}$ laser on optically shaped ${\mathrm{H}}_{2}$ and He gas targets. A low energy laser prepulse ($I\lesssim {10}^{14}\text{\hspace{0.17em}}\text{\hspace{0.17em}}\mathrm{W}\text{\hspace{0.17em}}{\mathrm{cm}}^{-2}$) is used to drive a blast wave inside the gas target, creating a steepened, variable density gradient. This is followed, after …

[Phys. Rev. Lett. 115, 094802] Published Fri Aug 28, 2015

]]>In order to understand the conditions that lead to a highly magnetized, relativistic plasma becoming unstable, and in such cases how the plasma evolves, we study a prototypical class of magnetostatic equilibria in which the magnetic field satisfies $\nabla \times \mathbf{B}=\alpha \mathbf{B}$, where $\alpha $ is spatially uniform, on a periodic…

[Phys. Rev. Lett. 115, 095002] Published Fri Aug 28, 2015

]]>Recently it has been theoretically proposed and experimentally demonstrated that a spin-orbit coupled multicomponent gas in a 1D lattice can be viewed as a spinless gas in a synthetic 2D lattice with a magnetic flux. In this Letter we consider interaction effects in such a Fermi gas, and propose the…

[Phys. Rev. Lett. 115, 095302] Published Fri Aug 28, 2015

]]>The melting of bismuth in response to shock compression has been studied using *in situ* femtosecond x-ray diffraction at an x-ray free electron laser. Both solid-solid and solid-liquid phase transitions are documented using changes in discrete diffraction peaks and the emergence of broad, liquid scat…

[Phys. Rev. Lett. 115, 095701] Published Fri Aug 28, 2015

]]>We report the formation and observation of an electron liquid in ${\mathrm{Sr}}_{2-x}{\mathrm{La}}_{x}{\mathrm{TiO}}_{4}$, the quasi-two-dimensional counterpart of ${\mathrm{SrTiO}}_{3}$, through reactive molecular-beam epitaxy and *in situ* angle-resolved photoemission spectroscopy. The lowest lying states are found to be comprised of Ti $3{d}_{xy}$ orbitals, analog…

[Phys. Rev. Lett. 115, 096405] Published Fri Aug 28, 2015

]]>We investigate the origin of the spin Seebeck effect in yttrium iron garnet (YIG) samples for film thicknesses from 20 nm to $50\text{\hspace{0.17em}}\text{\hspace{0.17em}}\mu \mathrm{m}$ at room temperature and 50 K. Our results reveal a characteristic increase of the longitudinal spin Seebeck effect amplitude with the thickness of the insulating ferrim…

[Phys. Rev. Lett. 115, 096602] Published Fri Aug 28, 2015

]]>We studied experimentally the dynamics of the exchange interaction between two antiparallel electron spins in an isolated double quantum dot where coupling to the electron reservoirs can be ignored. We demonstrate that the level of control of such a double dot is higher than in conventional double d…

[Phys. Rev. Lett. 115, 096801] Published Fri Aug 28, 2015

]]>Transport in three-dimensional topological insulators relies on the existence of a spin-momentum locked surface state that encloses the insulating bulk. In this work we show how, in a topological insulator $p\text{\u2212}n$ junction, a magnetic field turns this surface state into an electronic Mach-Zehnder interf…

[Phys. Rev. Lett. 115, 096802] Published Fri Aug 28, 2015

]]>We show that the superconducting order parameter and condensation energy density of phonon-mediated superconductors can be calculated in real space from first principles density functional theory for superconductors. This method highlights the connection between the chemical bonding structure and th…

[Phys. Rev. Lett. 115, 097002] Published Fri Aug 28, 2015

]]>A magnetic helix realizes a one-dimensional magnetic crystal with a period given by the pitch length ${\lambda}_{h}$. Its spin-wave excitations—the helimagnons—experience Bragg scattering off this periodicity, leading to gaps in the spectrum that inhibit their propagation along the pitch direction. Using high-re…

[Phys. Rev. Lett. 115, 097203] Published Fri Aug 28, 2015

]]>We introduce fractal liquids by generalizing classical liquids of integer dimensions $d=1,2,3$ to a noninteger dimension ${d}_{l}$. The particles composing the liquid are fractal objects and their configuration space is also fractal, with the same dimension. Realizations of our generic model system include m…

[Phys. Rev. Lett. 115, 097801] Published Fri Aug 28, 2015

]]>Nontrivial topological modulations, including skyrmions and knots, are observed in the magnetic field configurations of poly and monodomain chiral ferromagnetic liquid crystal colloids.

[Phys. Rev. Lett. 115, 097802] Published Fri Aug 28, 2015

]]>The spontaneous transitions between $D$-dimensional spatial maps in an attractor neural network are studied. Two scenarios for the transition from one map to another are found, depending on the level of noise: (i) through a mixed state, partly localized in both maps around positions where the maps are…

[Phys. Rev. Lett. 115, 098101] Published Fri Aug 28, 2015

]]>We study how local rearrangements alter droplet stresses within flowing dense quasi-two-dimensional emulsions at area fractions $\varphi \ge 0.88$. Using microscopy, we measure droplet positions while simultaneously using their deformed shape to measure droplet stresses. We find that rearrangements alter nearby…

[Phys. Rev. Lett. 115, 098302] Published Fri Aug 28, 2015

]]>In this Letter we study the problem of secrecy reversibility. This asks when two honest parties can distill secret bits from some tripartite distribution ${p}_{XYZ}$ and transform secret bits back into ${p}_{XYZ}$ at equal rates using local operation and public communication. This is the classical analog to the w…

[Phys. Rev. Lett. 115, 090501] Published Thu Aug 27, 2015

]]>Periodically driven thermodynamic systems near equilibrium cannot have finite fluxes with zero dissipation.

[Phys. Rev. Lett. 115, 090601] Published Thu Aug 27, 2015

]]>In the context of neutron star mergers, we study the gravitational wave spectrum of the merger remnant using numerical relativity simulations. Postmerger spectra are characterized by a main peak frequency ${f}_{2}$ related to the particular structure and dynamics of the remnant hot hypermassive neutron sta…

[Phys. Rev. Lett. 115, 091101] Published Thu Aug 27, 2015

]]>We clarify the higher-dimensional origin of a class of dyonic gaugings of $D=4\text{\hspace{0.17em}}\text{\hspace{0.17em}}\mathcal{N}=8$ supergravity recently discovered, when the gauge group is chosen to be ISO(7). This dyonically gauged maximal supergravity arises from consistent truncation of massive IIA supergravity on ${S}^{6}$, and its magnetic coupling…

[Phys. Rev. Lett. 115, 091601] Published Thu Aug 27, 2015

]]>Measurements of the total and differential cross sections of Higgs boson production are performed using $20.3\text{\hspace{0.17em}}\text{\hspace{0.17em}}{\mathrm{fb}}^{-1}$ of $pp$ collisions produced by the Large Hadron Collider at a center-of-mass energy of $\sqrt{s}=8\text{\hspace{0.17em}}\text{\hspace{0.17em}}\mathrm{TeV}$ and recorded by the ATLAS detector. Cross sections are obtained from measured $H\to \gamma \gamma $ and $H\to Z{Z}^{\dots}$

[Phys. Rev. Lett. 115, 091801] Published Thu Aug 27, 2015

]]>We report an observation of the process $J/\psi \to \gamma X(1835)\to \gamma {K}_{S}^{0}{K}_{S}^{0}\eta $ at low ${K}_{S}^{0}{K}_{S}^{0}$ mass with a statistical significance larger than $12.9\sigma $ using a data sample of $1.31\times {10}^{9}$ $J/\psi $ events collected with the BESIII detector. In this region of phase space the ${K}_{S}^{0}{K}_{S}^{0}$ system is dominantly produced through the ${f}_{0}(980)$…

[Phys. Rev. Lett. 115, 091803] Published Thu Aug 27, 2015

]]>We show how to use two-mode squeezed light to exponentially enhance cavity-based dispersive qubit measurement. Our scheme enables true Heisenberg-limited scaling of the measurement, and crucially, it is not restricted to small dispersive couplings or unrealistically long measurement times. It involv…

[Phys. Rev. Lett. 115, 093604] Published Thu Aug 27, 2015

]]>We investigate the Loschmidt echo, the overlap of the initial and final wave functions of Luttinger liquids after a spatially inhomogeneous interaction quench. In studying the Luttinger model, we obtain an analytic solution of the bosonic Bogoliubov–de Gennes equations after quenching the interactio…

[Phys. Rev. Lett. 115, 096403] Published Thu Aug 27, 2015

]]>We investigate the polaronic ground state of anatase ${\mathrm{TiO}}_{2}$ by bulk-sensitive resonant inelastic x-ray spectroscopy (RIXS) at the Ti ${L}_{3}$ edge. We find that the formation of the polaron cloud involves a single 95 meV phonon along the $c$ axis, in addition to the 108 meV $ab$-plane mode previously identified…

[Phys. Rev. Lett. 115, 096404] Published Thu Aug 27, 2015

]]>We report the low-temperature magnetic properties of ${\mathrm{Ce}}_{2}{\mathrm{Sn}}_{2}{\mathrm{O}}_{7}$, a rare-earth pyrochlore. Our susceptibility and magnetization measurements show that due to the thermal isolation of a Kramers doublet ground state, ${\mathrm{Ce}}_{2}{\mathrm{Sn}}_{2}{\mathrm{O}}_{7}$ has Ising-like magnetic moments of $\sim 1.18\text{\hspace{0.17em}}\text{\hspace{0.17em}}{\mu}_{B}$. The magnetic moments are confined…

[Phys. Rev. Lett. 115, 097202] Published Thu Aug 27, 2015

]]>We report a new limitation on the ability of physical systems to perform computation—one that is based on generalizing the notion of memory, or storage space, available to the system to perform the computation. Roughly, we define memory as the maximal amount of information that the evolving system c…

[Phys. Rev. Lett. 115, 098701] Published Thu Aug 27, 2015

]]>The free-streaming cosmic neutrino background has been observed by a unique decomposition of the acoustic oscillations in the cosmic microwave background.

[Phys. Rev. Lett. 115, 091301] Published Wed Aug 26, 2015

]]>Some extensions of the standard model suggest the existence of vectorlike fermions whose mass $M$ can be larger by up to several orders of magnitude than the electroweak scale $v$, and with the Higgs mechanism providing only a small part $m$ of this mass that is a fraction of $v$. It is shown that in a cert…

[Phys. Rev. Lett. 115, 091802] Published Wed Aug 26, 2015

]]>Measurements from STAR collaboration experiments at RHIC reveal that gluons and quarks may contribute equally to the spin angular momentum of a proton.

[Phys. Rev. Lett. 115, 092002] Published Wed Aug 26, 2015

]]>We investigate the transport of excitations through a chain of atoms with nonlocal dissipation introduced through coupling to additional short-lived states. The system is described by an effective spin-$1/2$ model where the ratio of the exchange interaction strength to the reservoir coupling strength …

[Phys. Rev. Lett. 115, 093002] Published Wed Aug 26, 2015

]]>We demonstrate an all-fiber cavity quantum electrodynamics system with a trapped single atom in the strong coupling regime. We use a nanofiber Fabry-Perot cavity, that is, an optical nanofiber sandwiched by two fiber-Bragg-grating mirrors. Measurements of the cavity transmission spectrum with a sing…

[Phys. Rev. Lett. 115, 093603] Published Wed Aug 26, 2015

]]>Wave scattering provides profound insight into the structure of matter. Typically, the ability to sense microstructure is determined by the ratio of scatterer size to probing wavelength. Here, we address the question of whether macroscopic waves can report back the presence and distribution of micro…

[Phys. Rev. Lett. 115, 094301] Published Wed Aug 26, 2015

]]>We report on a new method for realizing an exceptionally strong inertial confinement of a gas in a liquid: A centimetric spherical bubble filled with a reactive gaseous mixture in a liquid is expanded by an exothermic chemical reaction whose products condense in the liquid at the bubble wall. Hence,…

[Phys. Rev. Lett. 115, 094501] Published Wed Aug 26, 2015

]]>The spin precession frequency of a charged particle in a storage ring is determined with substantially increased precision. This allows for improved measurements of the electric dipole moments of charged particles.

[Phys. Rev. Lett. 115, 094801] Published Wed Aug 26, 2015

]]>Ultracold atoms in an optical lattice could be imaged on length scales below the diffraction limit by tracking the collapse of the system’s many-body wavefunction.

[Phys. Rev. Lett. 115, 095301] Published Wed Aug 26, 2015

]]>Using scanning tunneling microscopy and density functional theory, we show that the molecular ordering and orientation of metal phthalocyanine molecules on the deactivated Si surface display a strong dependency on the central transition-metal ion, driven by the degree of orbital hybridization at the…

[Phys. Rev. Lett. 115, 096101] Published Wed Aug 26, 2015

]]>The insulating ground state of the $5d$ transition metal oxide ${\mathrm{CaIrO}}_{3}$ has been classified as a Mott-type insulator. Based on a systematic density functional theory (DFT) study with local, semilocal, and hybrid exchange-correlation functionals, we reveal that the Ir ${t}_{2g}$ states exhibit large splittings …

[Phys. Rev. Lett. 115, 096401] Published Wed Aug 26, 2015

]]>The magnetic properties of gadolinium at non-zero temperature are different at the surface of the material and in the bulk for both the paramagnetic and ferromagnetic phases according to layer resolved density-functional theory calculations.

[Phys. Rev. Lett. 115, 096402] Published Wed Aug 26, 2015

]]>We show how an electrical measurement can detect the pairing of electrons on the same side of the Fermi surface (Amperian pairing), recently proposed by Patrick Lee for the pseudogap phase of high-${T}_{c}$ cuprate superconductors. Bragg scattering from the pair-density wave introduces odd multiples of $2{k}_{F}$…

[Phys. Rev. Lett. 115, 097001] Published Wed Aug 26, 2015

]]>A new technique — spinning-current anomalous Hall magnetometry — measures the field invariant magnetization of antiferromagnets with high precision by cycling current and voltage probes.

[Phys. Rev. Lett. 115, 097201] Published Wed Aug 26, 2015

]]>The spin polarization of Pt in $\mathrm{Pt}/{\mathrm{NiFe}}_{2}{\mathrm{O}}_{4}$ and $\mathrm{Pt}/\mathrm{Fe}$ bilayers is studied by interface-sensitive x-ray resonant magnetic reflectivity to investigate static magnetic proximity effects. The asymmetry ratio of the reflectivity is measured at the Pt ${L}_{3}$ absorption edge using circular polarized x-rays for o…

[Phys. Rev. Lett. 115, 097401] Published Wed Aug 26, 2015

]]>Ferroelectrics and antiferroelectrics appear to have just the opposite behavior upon scaling down. Below a critical thickness of just a few nanometers the ferroelectric phase breaks into nanodomains that mimic electric properties of antiferroelectrics very closely. On the other hand, antiferroelectr…

[Phys. Rev. Lett. 115, 097601] Published Wed Aug 26, 2015

]]>We calculate the amplitude for exclusive neutrino production of a charmed meson on an unpolarized target in the collinear QCD approach, where generalized parton distributions (GPDs) factorize from perturbatively calculable coefficient functions. We demonstrate that the transversity chiral odd GPDs c…

[Phys. Rev. Lett. 115, 092001] Published Tue Aug 25, 2015

]]>Rogue waves are observed as light propagates in the extreme nonlinear regime that occurs when a photorefractive ferroelectric crystal is undergoing a structural phase transition. The transmitted spatial light distribution contains bright localized spots of anomalously large intensity that follow a s…

[Phys. Rev. Lett. 115, 093901] Published Tue Aug 25, 2015

]]>Time-dependent density functional theory for quantum electrodynamics is successfully applied to electronic structure calculations via a quantum-optical treatment of the electromagnetic field.

[Phys. Rev. Lett. 115, 093001] Published Mon Aug 24, 2015

]]>We demonstrate $|W\u27e9$ state encoding of multiatom ensemble qubits. Using optically trapped Rb atoms, the ${T}_{2}$ coherence time is 2.6(3) ms for $\overline{N}=7.6$ atoms and scales approximately inversely with the number of atoms. Strong Rydberg blockade between two ensemble qubits is demonstrated with a fidelity of 0.…

[Phys. Rev. Lett. 115, 093601] Published Mon Aug 24, 2015

]]>All-optical addressing and coherent control of single solid-state based quantum bits is a key tool for fast and precise control of ground-state spin qubits. So far, all-optical addressing of qubits was demonstrated only in a very few systems, such as color centers and quantum dots. Here, we perform …

[Phys. Rev. Lett. 115, 093602] Published Mon Aug 24, 2015

]]>We perform full-magnetohydrodynamics simulations on various initially helical configurations and show that they reconfigure into a state where the magnetic field lines span nested toroidal surfaces. This relaxed configuration is not a Taylor state, as is often assumed for relaxing plasma, but a stat…

[Phys. Rev. Lett. 115, 095001] Published Mon Aug 24, 2015

]]>X-ray magnetic circular dichroism detects the transient magnetic moments that are induced in a nonmagnetic material by spin injection from a ferromagnet.

[Phys. Rev. Lett. 115, 096601] Published Mon Aug 24, 2015

]]>A theory for jammed granular materials is developed with the aid of a nonequilibrium steady-state distribution function. The approximate nonequilibrium steady-state distribution function is explicitly given in the weak dissipation regime by means of the relaxation time. The theory quantitatively agr…

[Phys. Rev. Lett. 115, 098001] Published Mon Aug 24, 2015

]]>We study numerically a model for active suspensions of self-propelled repulsive particles, for which a stable phase separation into a dilute and a dense phase is observed. We exploit the fact that for nonsquare boxes a stable “slab” configuration is reached, in which interfaces align with the shorte…

[Phys. Rev. Lett. 115, 098301] Published Mon Aug 24, 2015

]]>Counterfactual computation (CFC) exemplifies the fascinating quantum process by which the result of a computation may be learned without actually running the computer. In previous experimental studies, the counterfactual efficiency is limited to below 50%. Here we report an experimental realization …

[Phys. Rev. Lett. 115, 080501] Published Fri Aug 21, 2015

]]>We study a Brownian particle passively driven by a field obeying the noisy Burgers’ equation. We demonstrate that the system exhibits replica symmetry breaking in the path ensemble with the initial position of the particle being fixed. The key step of the proof is that the path ensemble with a modif…

[Phys. Rev. Lett. 115, 080605] Published Fri Aug 21, 2015

]]>We consider spherically symmetric Einstein-massless-scalar field equations with a negative cosmological constant in five dimensions and analyze the evolution of small perturbations of anti–de Sitter (AdS) spacetime using the recently proposed resonant approximation. We show that for typical initial …

[Phys. Rev. Lett. 115, 081103] Published Fri Aug 21, 2015

]]>We calculate the fully differential next-to-next-to-leading-order (NNLO) corrections to vector-boson fusion (VBF) Higgs boson production at proton colliders, in the limit in which there is no cross talk between the hadronic systems associated with the two protons. We achieve this using a new “projec…

[Phys. Rev. Lett. 115, 082002] Published Fri Aug 21, 2015

]]>We present precise predictions for Higgs boson production in association with a jet. We work in the Higgs effective field theory framework and compute next-to-next-to-leading order QCD corrections to the gluon-gluon and quark-gluon channels, which is sufficient for reliable LHC phenomenology. We pre…

[Phys. Rev. Lett. 115, 082003] Published Fri Aug 21, 2015

]]>A novel approach is used for the simulation of decagonal quasicrystal (DQC) solidification and growth. It is based on the observation that in well-ordered DQCs the atoms are largely arranged along quasiperiodically spaced planes parallel to the tenfold axis, running throughout the whole structure in…

[Phys. Rev. Lett. 115, 085502] Published Fri Aug 21, 2015

]]>Crystal morphologies are important for the design and functionality of devices based on low-dimensional nanomaterials. The equilibrium crystal shape (ECS) is a key quantity in this context. It is determined by surface energies, which are hard to access experimentally but can generally be well predic…

[Phys. Rev. Lett. 115, 085503] Published Fri Aug 21, 2015

]]>We address the controversy over the spin transport mechanism in ${\mathrm{Alq}}_{3}$ utilizing spin pumping in the ${\mathrm{Y}}_{3}{\mathrm{Fe}}_{5}{\mathrm{O}}_{12}/{\mathrm{Alq}}_{3}/\mathrm{Pd}$ system. An unusual angular dependence of the inverse spin Hall effect is found. It, however, disappears when the microwave magnetic field is fully in the sample plane, excluding the pr…

[Phys. Rev. Lett. 115, 086601] Published Fri Aug 21, 2015

]]>Ultrafast dynamics of photoexcited electron-hole pairs produced by 10 femtosecond pulses in graphene may have implications for petahertz electronic and optoelectronic devices.

[Phys. Rev. Lett. 115, 086803] Published Fri Aug 21, 2015

]]>High quality ${\mathrm{HgCr}}_{2}{\mathrm{Se}}_{4}$ single crystals have been investigated by magnetization, electron transport, and Andreev reflection spectroscopy. In the ferromagnetic ground state, the saturation magnetic moment of each unit cell corresponds to an integer number of electron spins ($3\text{\hspace{0.17em}}\text{\hspace{0.17em}}{\mu}_{B}/{\mathrm{Cr}}^{3+}$), and the Hall ef…

[Phys. Rev. Lett. 115, 087002] Published Fri Aug 21, 2015

]]>We show from a weak-coupling microscopic calculation that the most favored chiral superconducting order parameter in ${\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4}$ has a Chern number of $|C|=7$. The two dominant components of this order parameter are given by $\mathrm{sin}(3{k}_{x})+i\mathrm{sin}(3{k}_{y})$ and $\mathrm{sin}({k}_{x})\mathrm{cos}({k}_{y})+i\mathrm{sin}({k}_{y})\mathrm{cos}({k}_{x})$ and lie in the same irreduc…

[Phys. Rev. Lett. 115, 087003] Published Fri Aug 21, 2015

]]>Thermodynamic properties of chiral spin liquids are investigated for a variant of the Kitaev model defined on a decorated honeycomb lattice. Using the quantum Monte Carlo simulation, we find that the model exhibits a finite-temperature phase transition associated with the time reversal symmetry brea…

[Phys. Rev. Lett. 115, 087203] Published Fri Aug 21, 2015

]]>Recently studied hyperbolic materials host unique phonon-polariton (PP) modes. The ultrashort wavelengths of these modes, as well as their low damping, hold promise for extreme subdiffraction nanophotonics schemes. Polar hyperbolic materials such as hexagonal boron nitride can be used to realize lon…

[Phys. Rev. Lett. 115, 087401] Published Fri Aug 21, 2015

]]>We show that electric field noise from surface charge fluctuations can be a significant source of spin decoherence for near-surface nitrogen-vacancy (NV) centers in diamond. This conclusion is based on the increase in spin coherence observed when the diamond surface is covered with high-dielectric-c…

[Phys. Rev. Lett. 115, 087602] Published Fri Aug 21, 2015

]]>[Phys. Rev. Lett. 115, 089902] Published Fri Aug 21, 2015

]]>Dynamic nuclear polarization (DNP) is to date the most effective technique to increase the nuclear polarization opening disruptive perspectives for medical applications. In a DNP setting, the interacting spin system is quasi-isolated and brought out of equilibrium by microwave irradiation. Here we s…

[Phys. Rev. Lett. 115, 080401] Published Thu Aug 20, 2015

]]>We present a theoretical method to study driven-dissipative correlated quantum systems on lattices with two spatial dimensions (2D). The steady-state density matrix of the lattice is obtained by solving the master equation in a corner of the Hilbert space. The states spanning the corner space are de…

[Phys. Rev. Lett. 115, 080604] Published Thu Aug 20, 2015

]]>Using Earth as a neutrino filter, the IceCube neutrino experiment strengthens its claim that it has detected neutrinos from powerful astrophysical accelerators outside our Galaxy.

[Phys. Rev. Lett. 115, 081102] Published Thu Aug 20, 2015

]]>We experimentally and theoretically study the diffraction phase of large-momentum transfer beam splitters in atom interferometers based on Bragg diffraction. We null the diffraction phase and increase the sensitivity of the interferometer by combining Bragg diffraction with Bloch oscillations. We de…

[Phys. Rev. Lett. 115, 083002] Published Thu Aug 20, 2015

]]>A system of optical fibers and cavities is used to simulate noise-assisted transport through a network. This system could potentially allow the contribution of noise to the transport of light in a complex system, analogous to photosynthesis, to be studied.

[Phys. Rev. Lett. 115, 083601] Published Thu Aug 20, 2015

]]>We experimentally study the effects of the anisotropic Rydberg interaction on $D$-state Rydberg polaritons slowly propagating through a cold atomic sample. We observe the interaction-induced dephasing of Rydberg polaritons at very low photon input rates into the medium. We develop a model combining th…

[Phys. Rev. Lett. 115, 083602] Published Thu Aug 20, 2015

]]>Nonlinear frequency conversion offers an effective way to expand the laser wavelength range based on birefringence phase matching (BPM) or quasi-phase-matching (QPM) techniques in nonlinear crystals. So far, efficient high-harmonic generation is enabled only via multiple cascaded crystals because of…

[Phys. Rev. Lett. 115, 083902] Published Thu Aug 20, 2015

]]>We probe the excitation spectrum of an ultracold one-dimensional Bose gas of cesium atoms with a repulsive contact interaction that we tune from the weakly to the strongly interacting regime via a magnetic Feshbach resonance. The dynamical structure factor, experimentally obtained using Bragg spectr…

[Phys. Rev. Lett. 115, 085301] Published Thu Aug 20, 2015

]]>The study of how molecules adsorb, diffuse, interact, and desorb from imperfect surfaces is essential for a complete understanding of elementary surface processes under relevant pressure and temperature conditions. Here we use first-principles calculations to study the adsorption of benzene and naph…

[Phys. Rev. Lett. 115, 086101] Published Thu Aug 20, 2015

]]>Topological crystalline insulators (TCIs) are insulating materials whose topological property relies on generic crystalline symmetries. Based on first-principles calculations, we study a three-dimensional (3D) crystal constructed by stacking two-dimensional TCI layers. Depending on the interlayer in…

[Phys. Rev. Lett. 115, 086802] Published Thu Aug 20, 2015

]]>We combine scanning-tunneling-spectroscopy experiments probing magnetic impurities on a superconducting surface with a theoretical analysis of the tunneling processes between (superconducting) tip and substrate. We show that the current through impurity-induced Shiba bound states is carried by singl…

[Phys. Rev. Lett. 115, 087001] Published Thu Aug 20, 2015

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