Thermoelastic-damping noise from sapphire mirrors in a fundamental-noise-limited interferometer

We report the first high-precision interferometer using large sapphire mirrors, and we present the first direct, broadband measurements of the fundamental thermal noise in these mirrors. Our results agree well with the thermoelastic-damping noise predictions of Braginsky, et al. [Phys. Lett. A 264, 1(1999)] and Cerdonio, et al.[Phys. Rev. D 63, 082003 (2001)], which have been used to predict the astrophysical reach of advanced interferometric gravitational wave detectors.Comment: 4 pages, 2 figure

Using boundary methods to compute the Casimir energy

We discuss new approaches to compute numerically the Casimir interaction energy for waveguides of arbitrary section, based on the boundary methods traditionally used to compute eigenvalues of the 2D Helmholtz equation. These methods are combined with the Cauchy's theorem in order to perform the sum over modes. As an illustration, we describe a point-matching technique to compute the vacuum energy for waveguides containing media with different permittivities. We present explicit numerical evaluations for perfect conducting surfaces in the case of concentric corrugated cylinders and a circular cylinder inside an elliptic one.Comment: To be published in the Proceedings of QFEXT09, Norman, OK

Keck Observations of the Hidden Quasar IRAS P09104+4109

We present imaging and spectro- polarimetric observations of the ultraluminous infrared galaxy IRAS P09104+4109 using the Keck 10-m Telescope. We detect the clear presence of broad Hb, Hg, and MgII 2800 emission lines in the polarized flux spectra of the nucleus and of an extranuclear emission region ~ 4" away, confirming the presence of a hidden central quasar. The polarization of the broad Mg II emission line is high (~ 29%), consistent with the remarkably high polarization (~ 30%-40%) observed in the extended continuum emission. The narrow emission lines are polarized in a stratified fashion, with the high ionization lines being polarized 0.7%-1.7% and [O II] essentially unpolarized. The line polarizations are positively correlated with critical density, ionization potential, and velocity width of the emission lines. This indicates that the NLR may be partially shadowed by the putative torus, with the higher ionization lines originating closer to the nucleus. One notable characteristic of the extranuclear knot is that all species of Fe are markedly absent in its spectrum, while they appear prominently in the nucleus. Our favored interpretation is that there is a large amount of dust in the extranuclear regions, allowing gaseous refractory metals to deposit. The extended emission regions are most likely material shredded from nearby cluster members and not gas condensed from the cooling flow or expelled from the obscured quasar. Our data provide strong evidence for matter-bounded clouds in addition to ionization-bounded clouds in the NLR. Ionization by pure velocity shocks can be ruled out. Shocks with photoionizing precursors may be present, but are probably not a dominant contributor to the energy input.Comment: 32 pages, including 9 figs and 2 tables, to be published in the Astronomical Journa

Revisiting the location and environment of the central engine in NGC1068

We revisit in this paper the location of the various components observed in the AGN of NGC1068. Discrepancies between previously published studies are explained, and a new measurement for the absolute location of the K-band emission peak is provided. It is found to be consistent with the position of the central engine as derived by Gallimore (1997), Capetti (1997) and Kishimoto (1999). A series of map overlays is then presented and discussed. Model predictions of dusty tori show that the nuclear unresolved NIR-MIR emission is compatible with a broad range of models: the nuclear SED alone does not strongly constrain the torus geometry, while placing reasonable constraints on its size and thickness. The extended MIR emission observed within the ionizing cone is shown to be well explained by the presence of optically thick dust clouds exposed to the central engine radiation and having a small covering factor. Conversely, a distribution of diffuse dust particles within the ionizing cone is discarded. A simple model for the H2 and CO emission observed perpendicularly to the axis of the ionizing cone is proposed. We show that a slight tilt between the molecular disc and the Compton thick central absorber naturally reproduces the observed distribution of H2 of CO emission.Comment: 17 pages, 11 figures, revised version for A&

Dynamical Casimir effect in superconducting circuits: a numerical approach

We present a numerical analysis of the particle creation for a quantum field in the presence of time dependent boundary conditions. Having in mind recent experiments involving superconducting circuits, we consider their description in terms of a scalar field in a one dimensional cavity satisfying generalized boundary conditions that involve a time-dependent linear combination of the field and its spatial and time derivatives. We evaluate numerically the Bogoliubov transformation between {\it in} and {\it out}-states and find that the rate of particle production strongly depends on whether the spectrum of the unperturbed cavity is equidistant or not, and also on the amplitude of the temporal oscillations of the boundary conditions. We provide analytic justifications for the different regimes found numerically.Comment: 20 pages. 11 figure

A vestige low metallicity gas shell surrounding the radio galaxy 0943-242 at z=2.92

Observations are presented showing the doublet CIV 1550 absorption lines superimposed on the CIV emission in the radio galaxy 0943-242. Within the errors, the redshift of the absorption system that has a column density of N_CIV = 10^{14.5 +- 0.1} cm-2 coincides with that of the deep Ly-alpha absorption trough observed by Rottgering et al. (1995). The gas seen in absorption has a resolved spatial extent of at least 13 kpc (the size of the extended emission line region). We first model the absorption and emission gas as co-spatial components with the same metallicity and degree of excitation. Using the information provided by the emission and absorption line ratios of CIV and Ly-alpha, we find that the observed quantities are incompatible with photoionization or collisional ionization of cloudlets with uniform properties. We therefore reject the possibility that the absorption and emission phases are co-spatial and favour the explanation that the absorption gas has low metallicity and is located further away from the host galaxy (than the emission line gas). The estimated low metallicity for the absorption gas in 0943-242 (Z \~ 1% solar) and its proposed location -outer halo outside the radio cocoon- suggest that its existence preceeds the observed AGN phase and is a vestige of the initial starburst at the onset of formation of the parent galaxy.Comment: 11 pages,5 figures, A&A accepte

Continuous variable entanglement measurement without phase locking

A new simple entanglement measurement method is proposed for the bright EPR beams generated from a non-degenerate optical parametric amplifier operating at deamplification. Due to the output signal and idler modes are frequency degenerate and in phase, the needed phase shift of interference for the measurement of the correlated phase quadratures and anti-correlated amplitude quadratures can be accomplished by a quarter-wave plate and a half wave plate without separating the signal and idler beam. Therefore, phase locking and local oscillators are avoided.Comment: 8 pages,3 figure

Generation of Kerr non-Gaussian motional states of trapped ions

Non-Gaussian states represent a powerful resource for quantum information protocols in the continuous variables regime. Cat states, in particular, have been produced in the motional degree of freedom of trapped ions by controlled displacements dependent on the ionic internal state. An alternative method harnesses the Kerr nonlinearity naturally existent in this kind of system. We present detailed calculations confirming its feasibility for typical experimental conditions. Additionally, this method permits the generation of complex non-Gaussian states with negative Wigner functions. Especially, superpositions of many coherent states are achieved at a fraction of the time necessary to produce the cat state.Comment: 6 pages, 5 figure