16,122 research outputs found

    Gravitational-Wave Implications for the Parity Symmetry of Gravity at GeV Scale

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    Gravitational waves generated by the coalescence of compact binary open a new window to test the fundamental properties of gravity in the strong-field and dynamical regime. In this work, we focus on the parity symmetry of gravity which, if broken, can leave imprints on the waveform of gravitational wave. We construct generalized waveforms with amplitude and velocity birefringence due to parity violation in the effect field theory formalism, then analyze the open data of the ten binary black-hole merger events and the two binary neutron-star merger events detected by LIGO and Virgo collaboration. We do not find any signatures of violation of gravitational parity conservation, thereby setting the lower bound of the parity-violating energy scale to be 0.070.07 GeV. This presents the first observational evidence of the parity conservation of gravity at high energy scale, about 17 orders of magnitude tighter than the constraints from the Solar system tests and binary pulsar observation. The third-generation gravitational-wave detector is capable of probing the parity-violating energy scale at O(102)\mathcal{O}(10^2) GeV

    Adaptive just-in-time code diversification

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    We present a method to regenerate diversified code dynamically in a Java bytecode JIT compiler, and to update the diversification frequently during the execution of the program. This way, we can significantly reduce the time frame in which attackers can let a program leak useful address space information and subsequently use the leaked information in memory exploits. A proof of concept implementation is evaluated, showing that even though code is recompiled frequently, we can achieved smaller overheads than the previous state of the art, which generated diversity only once during the whole execution of a program

    Power-Adaptive Computing System Design for Solar-Energy-Powered Embedded Systems

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    β\beta-decay half-lives of neutron-rich nuclei and matter flow in the rr-process

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    The β\beta-decay half-lives of neutron-rich nuclei with 20⩽Z⩽5020 \leqslant Z \leqslant 50 are systematically investigated using the newly developed fully self-consistent proton-neutron quasiparticle random phase approximation (QRPA), based on the spherical relativistic Hartree-Fock-Bogoliubov (RHFB) framework. Available data are reproduced by including an isospin-dependent proton-neutron pairing interaction in the isoscalar channel of the RHFB+QRPA model. With the calculated β\beta-decay half-lives of neutron-rich nuclei a remarkable speeding up of rr-matter flow is predicted. This leads to enhanced rr-process abundances of elements with A≳140A \gtrsim 140, an important result for the understanding of the origin of heavy elements in the universe.Comment: 14 pages, 4 figure

    Non-vanishing spin Hall currents in disordered spin-orbit coupling systems

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    Spin currents that flow perpendicular to the electric field direction are generic in metals and doped semiconductors with spin-orbit coupling. It has recently been argued that the spin Hall conductivity can be dominated by an intrinsic contribution which follows from Bloch state distortion in the presence of an electric field. Here we report on an numerical demonstration of the robustness of this effect in the presence of disorder scattering for the case of a two-dimensional electron-gas with Rashba spin-orbit interactions (R2DES).Comment: 4 pages, 3 figure

    Quantum Hall Conductivity in a Landau Type Model with a Realistic Geometry

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    In this paper, we revisit some quantum mechanical aspects related to the Quantum Hall Effect. We consider a Landau type model, paying a special attention to the experimental and geometrical features of Quantum Hall experiments. The resulting formalism is then used to compute explicitely the Hall conductivity from a Kubo formula.Comment: LaTeX, 1 eps figur
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