Crustal Oscillations of Slowly Rotating Relativistic Stars

We study low-amplitude crustal oscillations of slowly rotating relativistic stars consisting of a central fluid core and an outer thin solid crust. We estimate the effect of rotation on the torsional toroidal modes and on the interfacial and shear spheroidal modes. The results compared against the Newtonian ones for wide range of neutron star models and equations of state.Comment: 15 page

Maximum elastic deformations of relativistic stars

We present a method for calculating the maximum elastic quadrupolar deformations of relativistic stars, generalizing the previous Newtonian, Cowling approximation integral given by [G. Ushomirsky et al., Mon. Not. R. Astron. Soc. 319, 902 (2000)]. (We also present a method for Newtonian gravity with no Cowling approximation.) We apply these methods to the m = 2 quadrupoles most relevant for gravitational radiation in three cases: crustal deformations, deformations of crystalline cores of hadron-quark hybrid stars, and deformations of entirely crystalline color superconducting quark stars. In all cases, we find suppressions of the quadrupole due to relativity compared to the Newtonian Cowling approximation, particularly for compact stars. For the crust these suppressions are up to a factor ~6, for hybrid stars they are up to ~4, and for solid quark stars they are at most ~2, with slight enhancements instead for low mass stars. We also explore ranges of masses and equations of state more than in previous work, and find that for some parameters the maximum quadrupoles can still be very large. Even with the relativistic suppressions, we find that 1.4 solar mass stars can sustain crustal quadrupoles of a few times 10^39 g cm^2 for the SLy equation of state or close to 10^40 g cm^2 for equations of state that produce less compact stars. Solid quark stars of 1.4 solar masses can sustain quadrupoles of around 10^44 g cm^2. Hybrid stars typically do not have solid cores at 1.4 solar masses, but the most massive ones (~2 solar masses) can sustain quadrupoles of a few times 10^41 g cm^2 for typical microphysical parameters and a few times 10^42 g cm^2 for extreme ones. All of these quadrupoles assume a breaking strain of 0.1 and can be divided by 10^45 g cm^2 to yield the fiducial "ellipticities" quoted elsewhere.Comment: 21 pages, 11 figures, version accepted by PRD, including the corrected maximum hybrid star quadrupoles (from the erratum to the shear modulus calculation) and the corrected binding energy computatio

Proton Wires in an Electric Field: the Impact of Grotthuss Mechanism on Charge Translocation

We present the results of the modeling of proton translocation in finite H-bonded chains in the framework of two-stage proton transport model. We explore the influence of reorientation motion of protons, as well as the effect of electric field and proton correlations on system dynamics. An increase of the reorientation energy results in the transition of proton charge from the surrounding to the inner water molecules in the chain. Proton migration along the chain in an external electric field has a step-like character, proceeding with the occurrence of electric field threshold-type effects and drastic redistribution of proton charge. Electric field applied to correlated chains induces first a formation of ordered dipole structures for lower field strength, and than, with a further field strength increase, a stabilization of states with Bjerrum D-defects. We analyze the main factors responsible for the formation/annihilation of Bjerrum defects showing the strong influence of the complex interplay between reorientation energy, electric field and temperature in the dynamics of proton wire.Comment: 28 pages, 9 figure

On-ground tests of LISA PathFinder thermal diagnostics system

Thermal conditions in the LTP, the LISA Technology Package, are required to be very stable, and in such environment precision temperature measurements are also required for various diagnostics objectives. A sensitive temperature gauging system for the LTP is being developed at IEEC, which includes a set of thermistors and associated electronics. In this paper we discuss the derived requirements applying to the temperature sensing system, and address the problem of how to create in the laboratory a thermally quiet environment, suitable to perform meaningful on-ground tests of the system. The concept is a two layer spherical body, with a central aluminium core for sensor implantation surrounded by a layer of polyurethane. We construct the insulator transfer function, which relates the temperature at the core with the laboratory ambient temperature, and evaluate the losses caused by heat leakage through connecting wires. The results of the analysis indicate that, in spite of the very demanding stability conditions, a sphere of outer diameter of the order one metre is sufficient. We provide experimental evidence confirming the model predictions.Comment: 18 pages, 5 figures, LaTeX2e (compile with pdflatex), sumbitted to CQG. This paper is a significant extension of gr-qc/060109

On Bures fidelity of displaced squeezed thermal states

Fidelity plays a key role in quantum information and communication theory. Fidelity can be interpreted as the probability that a decoded message possesses the same information content as the message prior to coding and transmission. In this paper, we give a formula of Bures fidelity for displaced squeezed thermal states directly by the displacement and squeezing parameters and birefly discuss how the results can apply to quantum information theory.Comment: 10 pages with RevTex require

Acceleration disturbances and requirements for ASTROD I

ASTRODynamical Space Test of Relativity using Optical Devices I (ASTROD I) mainly aims at testing relativistic gravity and measuring the solar-system parameters with high precision, by carrying out laser ranging between a spacecraft in a solar orbit and ground stations. In order to achieve these goals, the magnitude of the total acceleration disturbance of the proof mass has to be less than 10−13 m s−2 Hz−1/2 at 0.1 m Hz. In this paper, we give a preliminary overview of the sources and magnitude of acceleration disturbances that could arise in the ASTROD I proof mass. Based on the estimates of the acceleration disturbances and by assuming a simple controlloop model, we infer requirements for ASTROD I. Our estimates show that most of the requirements for ASTROD I can be relaxed in comparison with Laser Interferometer Space Antenna (LISA).Comment: 19 pages, two figures, accepted for publication by Class. Quantum Grav. (at press

Lifetimes of states in 19Ne above the 15 O + alpha breakup threshold

The 15O(alpha,gamma)19Ne reaction plays a role in the ignition of Type I x-ray bursts on accreting neutron stars. The lifetimes of states in 19Ne above the 15O + alpha threshold of 3.53 MeV are important inputs to calculations of the astrophysical reaction rate. These levels in 19Ne were populated in the 3He(20Ne,alpha)19Ne reaction at a 20Ne beam energy of 34 MeV. The lifetimes of six states above the threshold were measured with the Doppler shift attenuation method (DSAM). The present measurements agree with previous determinations of the lifetimes of these states and in some cases are considerably more precise

Phonon Squeezed States Generated by Second Order Raman Scattering

We study squeezed states of phonons, which allow a reduction in the quantum fluctuations of the atomic displacements to below the zero-point quantum noise level of coherent phonon states. We investigate the generation of squeezed phonon states using a second order Raman scattering process. We calculate the expectation values and fluctuations of both the atomic displacement and the lattice amplitude operators, as well as the effects of the phonon squeezed states on macroscopically measurable quantities, such as changes in the dielectric constant. These results are compared with recent experiments.Comment: 4 pages, REVTE