83,774 research outputs found

    Feminism in philosophy of language: communicative speech acts

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    Book synopsis: The thirteen specially-commissioned essays in this volume are written by philosophers at the forefront of feminist scholarship, and are designed to provide an accessible and stimulating guide to a philosophical literature that has seen massive expansion in recent years. Ranging from history of philosophy through metaphysics to philosophy of science, they encompass all the core subject areas commonly taught in anglophone undergraduate and graduate philosophy courses, offering both an overview of and a contribution to the relevant debates. Together they testify to the intellectual value of feminism as a radicalizing energy internal to philosophical inquiry. This volume will be essential reading for any student or teacher of philosophy who is curious about the place of feminism in their subject

    Low-energy fusion caused by an interference

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    Fusion of two deuterons of room temperature energy is studied. The nuclei are in vacuum with no connection to any external source (electric or magnetic field, illumination, surrounding matter, traps, etc.) which may accelerate them. The energy of the two nuclei is conserved and remains small during the motion through the Coulomb barrier. The penetration through this barrier, which is the main obstacle for low-energy fusion, strongly depends on a form of the incident flux on the Coulomb center at large distances from it. In contrast to the usual scattering, the incident wave is not a single plane wave but the certain superposition of plane waves of the same energy and various directions, for example, a convergent conical wave. As a result of interference, the wave function close to the Coulomb center is determined by a cusp caustic which is probed by de Broglie waves. The particle flux gets away from the cusp and moves to the Coulomb center providing a not small probability of fusion (cusp driven tunneling). Getting away from a caustic cusp also occurs in optics and acoustics

    Large time asymptotics for the fluctuation SPDE in the Kuramoto synchronization model

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    We investigate the long-time asymptotics of the fluctuation SPDE in the Kuramoto synchronization model. We establish the linear behavior for large time and weak disorder of the quenched limit fluctuations of the empirical measure of the particles around its McKean-Vlasov limit. This is carried out through a spectral analysis of the underlying unbounded evolution operator, using arguments of perturbation of self-adjoint operators and analytic semigroups. We state in particular a Jordan decomposition of the evolution operator which is the key point in order to show that the fluctuations of the disordered Kuramoto model are not self-averaging.Comment: 34 pages, 5 figures; V2: introduction simplified, references added and typos correcte

    Multipartite quantum nonlocality under local decoherence

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    We study the nonlocal properties of two-qubit maximally-entangled and N-qubit Greenberger-Horne-Zeilinger states under local decoherence. We show that the (non)resilience of entanglement under local depolarization or dephasing is not necessarily equivalent to the (non)resilience of Bell-inequality violations. Apart from entanglement and Bell-inequality violations, we consider also nonlocality as quantified by the nonlocal content of correlations, and provide several examples of anomalous behaviors, both in the bipartite and multipartite cases. In addition, we study the practical implications of these anomalies on the usefulness of noisy Greenberger-Horne-Zeilinger states as resources for nonlocality-based physical protocols given by communication complexity problems. There, we provide examples of quantum gains improving with the number of particles that coexist with exponentially-decaying entanglement and non-local contents.Comment: 6 pages, 4 figure

    Angular Momentum Transfer in Vela-like Pulsar Glitches

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    The angular momentum transfer associated to Vela-like glitches has never been calculated {\em directly} within a realistic scenario for the storage and release of superfluid vorticity; therefore, the explanation of giant glitches in terms of vortices has not yet been tested against observations. We present the first physically reasonable model, both at the microscopic and macroscopic level (spherical geometry, n=1 polytropic density profile, density-dependent pinning forces compatible with vortex rigidity), to determine where in the star the vorticity is pinned, how much of it, and for how long. For standard neutron star parameters (M=1.4M,Rs=10M=1.4 M_{\odot}, R_s=10 km, Ω˙=Ω˙Vela=1010\dot{\Omega}=\dot{\Omega}_{\rm Vela}=-10^{-10} Hz s1^{-1}), we find that maximum pinning forces of order fm1015f_m\approx10^{15} dyn cm1^{-1} can accumulate ΔLgl1040\Delta L_{\rm gl}\approx10^{40} erg s of superfluid angular momentum, and release it to the crust at intervals Δtgl3\Delta t_{\rm gl}\approx3 years. This estimate of ΔLgl\Delta L_{\rm gl} is one order of magnitude smaller than what implied indirectly by current models for post-glitch recovery, where the core and inner-crust vortices are taken as physically disconnected; yet, it successfully yields the magnitudes observed in recent Vela glitches for {\em both} jump parameters, ΔΩgl\Delta\Omega_{\rm gl} and ΔΩ˙gl\Delta\dot{\Omega}_{\rm gl}, provided one assumes that only a small fraction (<10<10%) of the total star vorticity is coupled to the crust on the short timescale of a glitch. This is reasonable in our approach, where no layer of normal matter exists between the core and the inner-crust, as indicated by existing microscopic calculation. The new scenario presented here is nonetheless compatible with current post-glitch models.Comment: 11 pages, 4 figure

    Evolution of a metastable phase with a magnetic phase coexistence phenomenon and its unusual sensitivity to magnetic field cycling in the alloys Tb5-xLuxSi3 (x <= 0.7)

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    Recently, we reported an anomalous enhancement of the positive magnetoresistance beyond a critical magnetic field in Tb5Si3 in the magnetically ordered state, attributable to 'inverse metamagnetism'. This results in unusual magnetic hysteresis loops for the pressurized specimens, which are relevant to the topic of 'electronic phase separation'. In this paper, we report the influence of small substitutions of Lu for Tb, to show the evolution of these magnetic anomalies. We find that, at low temperatures, the high-field high-resistivity phase could be partially stabilized on returning the magnetic field to zero in many of these Lu substituted alloys, as measured through the electrical resistivity ({\rho}). Also, the relative fractions of this phase and the virgin phase appear to be controlled by a small tuning of the composition and temperature. Interestingly, at 1.8 K a sudden 'switch-over' of the value of {\rho} for this mixed phase to that for the virgin phase for some compositions is observed at low fields after a few field cycles, indicating metastability of this mixed phase

    Majorana fermions emerging from magnetic nanoparticles on a superconductor without spin-orbit coupling

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    There exists a variety of proposals to transform a conventional s-wave superconductor into a topological superconductor, supporting Majorana fermion mid-gap states. A necessary ingredient of these proposals is strong spin-orbit coupling. Here we propose an alternative system consisting of a one-dimensional chain of magnetic nanoparticles on a superconducting substrate. No spin-orbit coupling in the superconductor is needed. We calculate the topological quantum number of a chain of finite length, including the competing effects of disorder in the orientation of the magnetic moments and in the hopping energies, to identify the transition into the topologically nontrivial state (with Majorana fermions at the end points of the chain).Comment: 7 pages, 5 figure

    KxFe2-ySe2 single crystals: Floating-zone growth, Transport and Structural properties

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    Single crystals of superconducting KxFe2-ySe2 have been grown with the optical floating-zone technique under application of 8 bar of argon pressure. We found that large and high quality single crystals with dimensions of ~\varnothing6 \times 10 mm could be obtained at the termination of the grown ingot through quenching, while the remaining part of the ingot decomposed. As-grown single crystals commonly represent an intergrowth of two sets of the c-axis characterized by slightly different lattice constants. Single crystal of K0.80Fe1.81Se2 shows a superconducting transition at Tc = 31.6 K, leading to a near 100% expulsion of the external magnetic field in magnetization measurements. On the other hand, neutron-diffraction data indicate that superconductivity in the sample coexists with a iron-vacancy superstructure and static antiferromagnetic order. The anisotropic ratio of the upper critical field Hc2 for both H//c and H//ab configurations is \sim3.46
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