Physical Review Letters

Using mode-coupling theory, we derive a constitutive equation for the nonlinear rheology of dense colloidal suspensions under arbitrary time-dependent homogeneous flow. Generalizing previous results for simple shear, this allows the full tensorial structure of the theory to be identified. Macroscopi...

By using heteroepitaxy on two different GaAs templates, we have investigated the impact of anisotropic strain on the magnetocaloric effect (MCE) of MnAs. The temperature range, spread around room temperature, and the maximal MCE position are markedly different in the two epitaxial systems. Simulated...

A general new technique to solve the two-center problem with arbitrarily oriented deformed realistic potentials is demonstrated, which is based on the powerful potential separable expansion method. As an example, molecular single-particle spectra for ¹²C+¹²C→²⁴Mg are calculated using deformed Wood...

We experimentally demonstrate increased diffuse transmission of light through strongly scattering materials. Wave front shaping is used to selectively couple light to the open transport eigenchannels, specific solutions of Maxwell’s equations which the sample transmits fully, resulting in an incre...

The possibility of a magnetic field controlling the chirality of matter has been debated for a long time. Here, we report the successful induction of chirality in the noncentrosymmetric canted antiferromagnet, CuB₂O₄, by application of a low intensity static magnetic field. The chirality is reversed...

The number N(E) of complex zeros of the Riemann zeta function with positive imaginary part less than E is the sum of a “smooth” function N̅ (E) and a “fluctuation.” Berry and Keating have shown that the asymptotic expansion of N̅ (E) counts states of positive energy less th...

We show, experimentally and theoretically, that the application of modest voltages, U₀=(0.1–1)  kV, to LiNbO₃∶Fe crystals at sufficiently high temperatures, T≈(550–700) °C, leads to the formation of ultraslow shock waves (moving discontinuities) of the electron density owing to the re...

A novel dimensionless parameter, the particle moment number Pa, was derived using dimensional analysis of the particle-laden Navier-Stokes equations, in order to understand the underlying physics of turbulence modification by particles. A set of 80 previous experimental measurements where the turbu...

We report the Autler-Townes doublet demonstrating a novel type of coherent interaction of atoms not with photons but with a periodic crystal field when the atom is in flight through a crystal at high velocity. It was observed by the nonoptical X-VUV (vacuum-ultraviolet) double resonance of three-dim...

New high-T_c Fe-based superconducting compounds, AFe₂As₂ with A=K, Cs, K/Sr, and Cs/Sr, were synthesized. The T_c of KFe₂As₂ and CsFe₂As₂ is 3.8 and 2.6 K, respectively, which rises with partial substitution of Sr for K and Cs and peaks at 37 K for 50%–60% Sr substitution, and the compounds enter ...

In this Letter, we show that the fulfillment of uncertainty relations is a sufficient criterion for a quantum-mechanically permissible state. We specifically construct two pseudospin observables for an arbitrary nonpositive Hermitian matrix whose uncertainty relation is violated. This method enables...

We consider classes of translationally invariant black hole solutions whose equations of state closely resemble that of QCD at zero chemical potential. We use these backgrounds to compute the ratio ζ/s of bulk viscosity to entropy density. For a class of black holes that exhibits a first-order tran...

We present a quantum Monte Carlo study of the zero-temperature equation of state of neutron matter and the computation of the ¹S₀ pairing gap in the low-density regime with ρ<0.04  fm^-3. The system is described by a nonrelativistic nuclear Hamiltonian including both two- and three-nucleon i...

Molecular-dynamics simulations are used to investigate temperature relaxation between electrons and ions in a fully ionized, classical Coulomb plasma with minimal assumptions. Recombination is avoided by using like charges. The relaxation rate agrees with theory in the weak coupling limit (g≡poten...

A concrete and experimentally feasible example for testing the putative Majorana zero-energy state bound in a vortex is theoretically proposed for a parallel plate geometry of superfluid ³He-A phase. We examine the experimental setup in connection with ongoing rotating cryostat experiments. The theo...

Active sites for a thermally induced bimolecular two-step catalytic reaction (O₂→2O, O+CO→CO₂) that occurs on a Pt(113)(1×2) structure at around 160 K were studied by angular distribution measurements of desorbing product CO₂. It was found that the intrinsic activity level of two-atom-wide (00...

We report on measurements of the excitation spectrum of a strongly interacting Bose-Einstein condensate. A magnetic-field Feshbach resonance is used to tune atom-atom interactions in the condensate and to reach a regime where quantum depletion and beyond mean-field corrections to the condensate chem...

Variations of the spectra of plasmonic light emitted from the junction of a scanning tunneling microscope have been observed for different lateral positions of the scanning tunneling microscope tip on a Au(111) surface. Subnanometer spatial variations of the light emission intensity over a triangula...

We introduce optically tunable surfaces based upon metallic gold nanoparticles trapped in open, water-filled gold cavities. The optical properties of the surfaces change dramatically with the presence and location of the particles inside the cavities. The precise position of the particles is shown t...

In this Letter, I study the magnetic response of electron wave functions in a commensurate collinear antiferromagnet. I show that, at a special set of momenta, hidden antiunitary symmetry protects Kramers degeneracy of Bloch eigenstates against a magnetic field, pointing transversely to staggered ma...

In this Letter we make progress on a longstanding open problem of Aaronson and Ambainis [Theory of Computing 1, 47 (2005)]: we show that if U is a sparse unitary operator with a gap D in its spectrum, then there exists an approximate logarithm H of U which is also sparse. The sparsity pattern of H gets more dense as 1/D increases. This result can be interpreted as a way to convert between local continuous-time and local discrete-time quantum processes. As an example we show that the discrete-time coined quantum walk can be realised stroboscopically from an approximately local continuous-time quantum walk.

We study the dynamics of bright solitons formed in a Bose-Einstein condensate with attractive atomic interactions perturbed by a weak bichromatic optical lattice potential. The lattice depth is a biperiodic function of time with a zero mean, which realizes a flashing ratchet for matter-wave solitons. We find that the average velocity of a soliton and the soliton current induced by the ratchet depend on the number of atoms in the soliton. As a consequence, soliton transport can be induced through scattering of different solitons. In the regime when matter-wave solitons are narrow compared to the lattice period the dynamics is well described by the effective Hamiltonian theory.

We demonstrate in a superconducting qubit the conditional recovery ("uncollapsing") of a quantum state after a partial-collapse measurement. A weak measurement extracts information and results in a non-unitary transformation of the qubit state. However, by adding a rotation and a second partial measurement with the same strength, we erase the extracted information, canceling the effect of both measurements. The fidelity of the state recovery is measured using quantum process tomography and found to be above 70% for partial-collapse strength less than 0.6.

We study the head-on collision of two highly boosted equal mass, nonrotating black holes. We determine the waveforms, radiated energies, and mode excitation in the center of mass frame for a variety of boosts. For the first time we are able to compare analytic calculations, black hole perturbation theory, and strong field, nonlinear numerical calculations for this problem. Extrapolation of our results, which include velocities of up to 0.94c, indicate that in the ultra-relativistic regime about 143 % of the energy is converted into gravitational waves. This gives rise to a luminosity of order 10-2c5/G, the largest known so far in a black hole merger.

A method is introduced for distinguishing top jets (boosted, hadronically decaying top quarks) from light quark and gluon jets using jet substructure. The procedure involves parsing the jet cluster to resolve its subjets, and then imposing kinematic constraints. With this method, light quark or gluon jets with pT @ 1 TeV can be rejected with an efficiency of around 99% while retaining up to 40% of top jets. This reduces the dijet background to heavy resonances by a factor of ~ 10,000, thereby allowing resonance searches in to be extended into the all-hadronic channel. In addition, top-tagging can be used in events when one of the tops decays semi-leptonically, in events with missing energy, and in studies of b-tagging efficiency at high pT.

The magnetic scenario recently suggested in emphasizes the role of monopoles in strongly coupled quark-gluon plasma (sQGP) near/above the deconfinement temperature, and specifically predicts that they help reduce its viscosity by the "magnetic bottle" effect. Arguments for "magnetic liquid" in 1-2Tc based on lattice results of monopole density were provided in . Here we present results for monopole-(anti)monopole correlation functions from the same classical molecular dynamics simulations, which are found to be in good agreement with lattice results in . We show that the magnetic Coulomb coupling runs in the direction opposite to the electric one, as expected, and it is roughly inverse of the asymptotic freedom formula for the electric one. However, as T decreases to Tc, the magnetic coupling never gets too weak, with the plasma parameter always large enough (G > 1). This nicely agrees with empirical evidences from RHIC experiments, implying that magnetic objects cannot have large mean free path and should also form a good liquid with low viscosity.

Nuclides in the vicinity of 94Ag have been studied with the Penning trap mass spectrometer JYFLTRAP at IGISOL. The masses of the two-proton decay daughter 92Rh and the beta-decay daughter 94Pd of the high-spin isomer in 94Ag have been measured and the masses of 93Pd and 94Ag have been deduced. When combined with the data from the one-proton or two-proton decay experiments, the results lead to contradictory mass excess values for the high-spin isomer in 94Ag, -46370(170) \textkeV or -44970(100) \textkeV, corresponding to excitation energies of 6960(400) \textkeV or 8360(370) \textkeV, respectively.

We present a general approach for the development of electron-proton density functionals in multicomponent density functional theory, treating electrons and nuclei quantum mechanically without the Born-Oppenheimer approximation. The electron-proton functional is derived using an explicitly correlated electron-proton energy term. This functional provides accurate hydrogen nuclear densities, thereby enabling reliable calculations of molecular properties. This approach is computationally practical for relatively large molecular systems with key hydrogen nuclei treated quantum mechanically.

Resonant 2p X-ray absorption spectra of size-selected transition metal ions and clusters consisting of 1 n 200 atoms are reported. Remnants of atomic multiplet splitting in L2,3-edge X-ray absorption can be resolved up to the trimer, above which the overall line shape is already bulk-like. A strong cluster size dependence of the L2,3 branching ratio was found for titanium, vanadium, and cobalt clusters. While 3d electron delocalization increases with cluster size, the apparent 2p spin-orbit splitting remains constant within the error bars. The size dependence of the L2,3 branching ratio can be attributed to cluster size specific screening of the 2p-3d Coulomb interaction by 3d/4s valence electrons.

We calculate harmonic spectra and shapes of attosecond pulse trains using numerical solutions of Non-Born Oppenheimer time-dependent Shrödinger equation for 1-D H2 molecules in an intense laser pulse. A very strong signature of nuclear motion is seen in the time profiles of high order harmonics. In general the nuclear motion shortens the part of the attosecond pulse train originating from the first electron contribution but it may enhance the second electron contribution for longer pulses. The shape of time profiles of harmonics can thus be used for monitoring the nuclear motion.