The masses of neutron stars in neutron star binaries are observed to fall in a narrow mass range around $\sim 1.33M_{\odot }$. We explore the advantage of focusing on this region of the parameter space in gravitational-wave searches. We find that an all-sky (externally triggered) search with an optimally reduced template bank is expected to detect 14% (61%) more binary mergers than without the reduction. A reduced template bank can also represent significant improvement in technical cost. We also develop a more detailed search method using binary mass distribution, and find a sensitivity increase similar to that due to the reduced template bank.

We show that information about scattering data of a quantum field theory can be obtained from studying the system at finite density and low temperatures. In particular we consider models formulated on the lattice that can be exactly dualized to theories of conserved charge fluxes on lattice links. Apart from eliminating the complex action problem at nonzero chemical potential $\mu$, these dualizations allow for a particle world line interpretation of the dual fluxes from which one can extract data about the two-particle wave function. As an example we perform dual Monte Carlo simulations of the two-dimensional O(3) model at nonzero $\mu$ and finite volume, whose nonperturbative spectrum consists of a massive triplet of particles. At nonzero $\mu$ particles are induced in the system, which at sufficiently low temperature give rise to sectors of fixed particle number. We show that the scattering phase shifts can be obtained either from the critical chemical potential values separating the sectors or directly from the wave function in the two-particle sector. We find that both methods give excellent agreement with the exact result. We discuss the applicability and generality of the new approaches.

We present a study of the inclusive production of the $X(4140)$ state with the decay to the $J/\psi \varphi$ final state in hadronic collisions. Based on $10.4{\mathrm{fb}}^{-1}$ of $p\overline{p}$ collision data collected by the D0 experiment at the Fermilab Tevatron collider, we report the first evidence for the prompt production of an $X(4140)$ state and find the fraction of $X(4140)$ events originating from $b$ hadrons to be $f_b=0.39\pm 0.07(\text{stat})\pm 0.10(\text{syst})$. The ratio of the nonprompt $X(4140)$ production rate to the $B_s^0$ yield in the same channel is $R=0.19\pm 0.05(\text{stat})\pm 0.07(\text{syst})$. The values of the mass $M=4152.5\pm 1.7(\text{stat}{)}_{-5.4}^{+6.2}(\text{syst})\mathrm{MeV}$ and width $\mathrm{\Gamma }=16.3\pm 5.6(\text{stat})\pm 11.4(\text{syst})\mathrm{MeV}$ are consistent with previous measurements.

Masses adjacent to the classical waiting-point nuclide ${}^{130}\mathrm{Cd}$ have been measured by using the Penning-trap spectrometer ISOLTRAP at ISOLDE/CERN. We find a significant deviation of over 400 keV from earlier values evaluated by using nuclear beta-decay data. The new measurements show the reduction of the $N=82$ shell gap below the doubly magic ${}^{132}\mathrm{Sn}$. The nucleosynthesis associated with the ejected wind from type-II supernovae as well as from compact object binary mergers is studied, by using state-of-the-art hydrodynamic simulations. We find a consistent and direct impact of the newly measured masses on the calculated abundances in the $A=128–132$ region and a reduction of the uncertainties from the precision mass input data.

Utilizing a silicon nanobeam optomechanical crystal, we investigate the attractor diagram arising from the radiation pressure interaction between a localized optical cavity at ${\lambda }_c=1542\mathrm{nm}$ and a mechanical resonance at ${\omega }_m/2\pi =3.72\mathrm{GHz}$. At a temperature of $T_b\approx 10\mathrm{K}$, highly nonlinear driving of mechanical motion is observed via continuous wave optical pumping. Introduction of a time-dependent (modulated) optical pump is used to steer the system towards an otherwise inaccessible dynamically stable attractor in which mechanical self-oscillation occurs for an optical pump red detuned from the cavity resonance. An analytical model incorporating thermo-optic effects due to optical absorption heating is developed and found to accurately predict the measured device behavior.

We study the spectrum of fermion states localized within the vortex core of a weak-coupling $p$-wave superfluid. The low energy spectrum consists of two anomalous branches that generate a large density of states at the locations of the half cores of the vortex. Fermi liquid interactions significantly stretch the vortex structure, which leads to a Lifshitz transition in the effective Fermi surface of the vortex core fermions. We apply the results to the rotational dynamics of vortices in superfluid ${}^3\mathrm{He}\text{−}\mathrm{B}$ and find an explanation for the observed slow mode.

Grain boundaries in materials have substantial influences on device properties, for instance on mechanical stability or electronic minority carrier lifetime in multicrystalline silicon solar cells. This applies especially to asymmetric, less ordered or faceted interface portions. Here, we present the complex atomic interface structure of an asymmetric $\mathrm{\Sigma }9$ tilt grain boundary in silicon, observed by high resolution scanning transmission electron microscopy (HR-STEM) and explained by atomistic modeling and computer simulation. Structural optimization of interface models for the asymmetric $\mathrm{\Sigma }9$ and related symmetrical $\mathrm{\Sigma }9$ and $\mathrm{\Sigma }3$ tilt grain boundaries, by means of molecular-statics simulations with empirical silicon potentials in combination with first-principles calculations, results in a faceted asymmetric interface structure, whose grain-boundary energy is so low that it is likely to exist. The simulated local atomic structures match the observed HR-STEM images very well.

We investigate the properties of the collective plasmon excitations in Dirac semimetals by using the methods of relativistic field theory. We find a strong and narrow plasmon excitation whose frequency is in the terahertz (THz) range which may be important for practical applications. The properties of the plasmon appear universal for all Dirac semimetals, due to the large degeneracy of the quasiparticles and the small Fermi velocity, $v_F\ll c$. This universality is closely analogous to the phenomenon of “dimensional transmutation” that is responsible for the emergence of dimensionful scales in relativistic field theories such as quantum chromodynamics.

We explore the nonequilibrium response of Chern insulators. Focusing on the Haldane model, we study the dynamics induced by quantum quenches between topological and nontopological phases. A notable feature is that the Chern number, calculated for an infinite system, is unchanged under the dynamics following such a quench. However, in finite geometries, the initial and final Hamiltonians are distinguished by the presence or absence of edge modes. We study the edge excitations and describe their impact on the experimentally observable edge currents and magnetization. We show that, following a quantum quench, the edge currents relax towards new equilibrium values, and that there is light-cone spreading of the currents into the interior of the sample.

The surface of a three-dimensional topological electron system often hosts symmetry-protected gapless surface states. With the effect of electron interactions, these surface states can be gapped out without symmetry breaking by a surface topological order, in which the anyon excitations carry anomalous symmetry fractionalization that cannot be realized in a genuine two-dimensional system. We show that for a mirror-symmetry-protected topological crystalline insulator with mirror Chern number $n=4$, its surface can be gapped out by an anomalous ${\mathbb{Z}}_2$ topological order, where all anyons carry mirror-symmetry fractionalization $M^2=-1$. The identification of such anomalous crystalline symmetry fractionalization implies that in a two-dimensional ${\mathbb{Z}}_2$ spin liquid, the vison excitation cannot carry $M^2=-1$ if the spinon carries $M^2=-1$ or a half-integer spin.

We present an experimental and theoretical study exploring surface effects on the evolution of the metal-insulator transition in the model Mott-Hubbard compound Cr-doped ${\mathrm{V}}_2{\mathrm{O}}_3$. We find a microscopic domain formation that is clearly affected by the surface crystallographic orientation. Using scanning photoelectron microscopy and x-ray diffraction, we find that surface defects act as nucleation centers for the formation of domains at the temperature-induced isostructural transition and favor the formation of microscopic metallic regions. A density-functional theory plus dynamical mean-field theory study of different surface terminations shows that the surface reconstruction with excess vanadyl cations leads to doped, and hence more metallic, surface states, which explains our experimental observations.

Understanding the mechanism of high transition temperature ($T_{\mathrm{c}}$) superconductivity in cuprates has been hindered by the apparent complexity of their multilayered crystal structure. Using a cryogenic scanning tunneling microscopy (STM), we report on layer-by-layer probing of the electronic structures of all ingredient planes (BiO, SrO, ${\mathrm{CuO}}_2$) of ${\mathrm{Bi}}_2{\mathrm{Sr}}_2{\mathrm{CaCu}}_2{\mathrm{O}}_{8+\delta }$ superconductor prepared by argon-ion bombardment and annealing technique. We show that the well-known pseudogap (PG) feature observed by STM is inherently a property of the BiO planes and thus irrelevant directly to Cooper pairing. The SrO planes exhibit an unexpected van Hove singularity near the Fermi level, while the ${\mathrm{CuO}}_2$ planes are exclusively characterized by a smaller gap inside the PG. The small gap becomes invisible near $T_{\mathrm{c}}$, which we identify as the superconducting gap. The above results constitute severe constraints on any microscopic model for high $T_{\mathrm{c}}$ superconductivity in cuprates.

In ferromagnets, magnons may condense into a single quantum state. Analogous to superconductors, this quantum state may support transport without dissipation. Recent works suggest that longitudinal spin transport through a thin-film ferromagnet is an example of spin superfluidity. Although intriguing, this tantalizing picture ignores long-range dipole interactions; here, we demonstrate that such interactions dramatically affect spin transport. In single-film ferromagnets, “spin superfluidity” only exists at length scales (a few hundred nanometers in yttrium iron garnet) somewhat larger than the exchange length. Over longer distances, dipolar interactions destroy spin superfluidity. Nevertheless, we predict the reemergence of spin superfluidity in trilayer ferromagnet-normal metal-ferromagnet films that are $\sim 1\mu \mathrm{m}$ in size. Such systems also exhibit other types of long-range spin transport in samples that are several micrometers in size.

Biological composite materials are known to be tough, stiff, stable, viscoelastic bodies, that can creep, recover, absorb energy, and filter vibrations. Their multifunctionality is associated with their architectures, which often consist of mineral units surrounded by organic interfaces that play a key role in the performance of the entire composite. However, the confinement and small dimensions of these organic interfaces pose a challenge in measuring their physical properties by direct methods. We propose an indirect, experimental-analytical framework by which to probe the elastic and viscoelastic behavior of an individual interface. We demonstrate this framework on thin organic interfaces in the shell Pinna nobilis, and discuss its possible uses in various other micro- and nanoscale composite systems.

We propose a new approach for the study of the quadratic stochastic Euclidean bipartite matching problem between two sets of $N$ points each, $N\gg 1$. The points are supposed independently randomly generated on a domain $\mathrm{\Omega }\subset {\mathbb{R}}^d$ with a given distribution $\rho (\mathbf{x})$ on $\mathrm{\Omega }$. In particular, we derive a general expression for the correlation function and for the average optimal cost of the optimal matching. A previous ansatz for the matching problem on the flat hypertorus is obtained as a particular case.

In this Letter we present a novel version of “long-lived” gluinos in supersymmetric models with the gluino lightest ordinary supersymmetric particle (LOSP) and the axino lightest supersymmetric particle. Within certain ranges of the axion decay constant $f_a<1\times 10^{10}\mathrm{GeV}$, the gluino mass bounds are reduced to less than 1000 GeV. The best limits can be obtained by looking for decaying $R$ hadrons in the detector where the gluino decays to a gluon and axino in the calorimeters. Supersymmetry (SUSY) models with a gluino LOSP can occur over a significant region of parameter space in either mirage mediation or general gauge-mediated SUSY breaking models. The gluino LOSP is not constrained by cosmology, but in this scenario the axion or axino may be a good dark matter candidate.