Sensitivity of the Moment of Inertia of Neutron Stars to the Equation of State of Neutron-Rich Matter

The sensitivity of the stellar moment of inertia to the neutron-star matter equation of state is examined using accurately-calibrated relativistic mean-field models. We probe this sensitivity by tuning both the density dependence of the symmetry energy and the high density component of the equation of state, properties that are at present poorly constrained by existing laboratory data. Particularly attractive is the study of the fraction of the moment of inertia contained in the solid crust. Analytic treatments of the crustal moment of inertia reveal a high sensitivity to the transition pressure at the core-crust interface. This may suggest the existence of a strong correlation between the density dependence of the symmetry energy and the crustal moment of inertia. However, no correlation was found. We conclude that constraining the density dependence of the symmetry energy - through, for example, the measurement of the neutron skin thickness in 208Pb - will place no significant bound on either the transition pressure or the crustal moment of inertia.Comment: 25 pages, 8 figures, 5 table

The SoLid anti-neutrino detector's readout system

The SoLid collaboration have developed an intelligent readout system to reduce their 3200 silicon photomultiplier detector's data rate by a factor of 10000 whilst maintaining high efficiency for storing data from anti-neutrino interactions. The system employs an FPGA-level waveform characterisation to trigger on neutron signals. Following a trigger, data from a space time region of interest around the neutron will be read out using the IPbus protocol. In these proceedings the design of the readout system is explained and results showing the performance of a prototype version of the system are presented

Dimensionality effects on non-equilibrium electronic transport in Cu nanobridges

We report on non-equilibrium electronic transport through normal-metal (Cu) nanobridges coupled to large reservoirs at low temperatures. We observe a logarithmic temperature dependence of the zero-bias conductance, as well as a universal scaling behavior of the differential conductance. Our results are explained by electron-electron interactions in diffusive metals in the zero-dimensional limit.Comment: RevTex, 4 page

Achieving geodetic motion for LISA test masses: ground testing result

The low-frequency resolution of space-based gravitational wave observatories such as LISA (Laser Interferometry Space Antenna) hinges on the orbital purity of a free-falling reference test mass inside a satellite shield. We present here a torsion pendulum study of the forces that will disturb an orbiting test mass inside a LISA capacitive position sensor. The pendulum, with a measured torque noise floor below 10 fNm/sqrt{Hz} from 0.6 to 10 mHz, has allowed placement of an upper limit on sensor force noise contributions, measurement of the sensor electrostatic stiffness at the 5% level, and detection and compensation of stray DC electrostatic biases at the mV level.Comment: 4 pages (revtex4) with 4 figure

Hadron-quark mixed phase in hyperon stars

We analyze the different possibilities for the hadron-quark phase transition occurring in beta-stable matter including hyperons in neutron stars. We use a Brueckner-Hartree-Fock approach including hyperons for the hadronic equation of state and a generalized MIT bag model for the quark part. We then point out in detail the differences between Maxwell and Gibbs phase transition constructions including the effects of surface tension and electromagnetic screening. We find only a small influence on the maximum neutron star mass, whereas the radius of the star and in particular its internal structure are more affected.Comment: 11 pages, 9 figure

The Microscopic Approach to Nuclear Matter and Neutron Star Matter

We review a variety of theoretical and experimental investigations aimed at improving our knowledge of the nuclear matter equation of state. Of particular interest are nuclear matter extreme states in terms of density and/or isospin asymmetry. The equation of state of matter with unequal concentrations of protons and neutrons has numerous applications. These include heavy-ion collisions, the physics of rare, short-lived nuclei and, on a dramatically different scale, the physics of neutron stars. The "common denominator" among these (seemingly) very different systems is the symmetry energy, which plays a crucial role in both the formation of the neutron skin in neutron-rich nuclei and the radius of a neutron star (a system 18 orders of magnitude larger and 55 orders of magnitude heavier). The details of the density dependence of the symmetry energy are not yet sufficiently constrained. Throughout this article, our emphasis will be on the importance of adopting a microscopic approach to the many-body problem, which we believe to be the one with true predictive power.Comment: 56 pages, review article to appear in the International Journal of Modern Physics

Coulomb corrections to the extrinsic spin-Hall effect of a two-dimensional electron gas

We develop the microscopic theory of the extrinsic spin Hall conductivity of a two-dimensional electron gas, including skew-scattering, side-jump, and Coulomb interaction effects. We find that while the spin-Hall conductivity connected with the side-jump is independent of the strength of electron-electron interactions, the skew-scattering term is reduced by the spin-Coulomb drag, so the total spin current and the total spin-Hall conductivity are reduced for typical experimental mobilities. Further, we predict that in paramagnetic systems the spin-Coulomb drag reduces the spin accumulations in two different ways: (i) directly through the reduction of the skew-scattering contribution (ii) indirectly through the reduction of the spin diffusion length. Explicit expressions for the various contributions to the spin Hall conductivity are obtained using an exactly solvable model of the skew-scattering.Comment: The Coulomb corrections to the spin-Hall conductivity and spin accumulations to first order in strength of spin-orbit coupling and electron-electron interactions are include