189 research outputs found

    The Spin-Orbit Evolution of GJ 667C System: The Effect of Composition and Other Planet's Perturbations

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    Potentially habitable planets within the habitable zone of M-dwarfs are affected by tidal interaction. We studied the tidal evolution in GJ 667C using a numerical code we call TIDEV. We reviewed the problem of the dynamical evolution focusing on the effects that a rheological treatment, different compositions and the inclusion of orbital perturbations, have on the spin-down time and the probability to be trapped in a low spin-orbit resonance. Composition have a strong effect on the spin-down time, changing, in some cases, by almost a factor of 2 with respect to the value estimated for a reference Earth-like model. We calculated the time to reach a low resonance value (3:2) for the configuration of 6 planets. Capture probabilities are affected when assuming different compositions and eccentricities variations. We chose planets b and c to evaluate the probabilities of capture in resonances below 5:2 for two compositions: Earth-like and Waterworld planets. We found that perturbations, although having a secular effect on eccentricities, have a low impact on capture probabilities and noth- ing on spin-down times. The implications of the eccentricity variations and actual habitability of the GJ 667C system are discussed.Comment: 15 pages, 9 figures, 4 tables. Accepted for publication in MNRAS - V

    Ultrafast control of Rabi oscillations in a polariton condensate

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    We report the experimental observation and control of space and time-resolved light-matter Rabi oscillations in a microcavity. Our setup precision and the system coherence are so high that coherent control can be implemented with amplification or switching off of the oscillations and even erasing of the polariton density by optical pulses. The data is reproduced by a fundamental quantum optical model with excellent accuracy, providing new insights on the key components that rule the polariton dynamics.Comment: 5 pages, 3 figures, supplementary 7 pages, 4 figures. Supplementary videos: https://drive.google.com/folderview?id=0B0QCllnLqdyBNjlMLTdjZlNhbTQ&usp=sharin

    Mass and pressure constraints on galaxy clusters from interferometric SZ observations

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    Following on our previous study of an analytic parametric model to describe the baryonic and dark matter distributions in clusters of galaxies with spherical symmetry, we perform an SZ analysis of a set of simulated clusters and present their mass and pressure profiles. The simulated clusters span a wide range in mass, 2.0 x 10^14 Msun < M200 < 1.0 x 10^15Msun, and observations with the Arcminute Microkelvin Imager (AMI) are simulated through their Sunyaev- Zel'dovich (SZ) effect. We assume that the dark matter density follows a Navarro, Frenk and White (NFW) profile and that the gas pressure is described by a generalised NFW (GNFW) profile. By numerically exploring the probability distributions of the cluster parameters given simulated interferometric SZ data in the context of Bayesian methods, we investigate the capability of this model and analysis technique to return the simulated clusters input quantities. We show that considering the mass and redshift dependency of the cluster halo concentration parameter is crucial in obtaining an unbiased cluster mass estimate and hence deriving the radial profiles of the enclosed total mass and the gas pressure out to r200.Comment: 5 pages, 2 tables, 3 figure

    The Evolution of K* and the Halo Occupation Distribution since z=1.5: Observations vs. Simulations

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    We study the evolution of the K-band luminosity function (LF) and the Halo Occupation Distribution (HOD) using Subaru observations of 15 X-ray clusters at z=0.8-1.5 and compare the results with mock clusters (0<z<1.3) extracted from the Millennium Simulation and populated with galaxies using the semi-analytic model (SAM) of Bower et al., matched in mass to our observed sample. We find that the characteristic luminosity K* defined by a Shechter LF is consistent with SAM predictions, which mimic well the evolution of K* in z>1 rich clusters. However, we cannot distinguish between this model and a simple stellar population synthesis model invoking passive evolution with a formation redshift z~5 - consistent with the presence of an old red galaxy population ubiquitous in rich clusters at z=1.5. We also see a small difference (\Delta K*~0.5) between our clusters and studies of the field population at similar redshifts, suggesting only a weak dependence of the luminous (L>L*) part of the LF on environment. Turning to our HOD study, we find that within R_{500}, high-z clusters tend to host smaller numbers of galaxies to a magnitude K*+2 compared to their low-z counterparts. This behavior is also seen in the mock samples and is relatively insensitive to the average mass of the cluster haloes. In particular, we find significant correlations of the observed number of member cluster galaxies (N) with both z and cluster mass: N(M,z)=(53±1)(1+z)0.610.20+0.18(M/1014.3)0.86±0.05N(M,z)=(53\pm1)(1+z)^{-0.61^{+0.18}_{-0.20}}(M/10^{14.3})^{0.86\pm0.05}. Finally, we examine the spatial distribution of galaxies and provide a new estimate of the concentration parameter for clusters at high z (cg=2.80.8+1.0c_{g}=2.8^{+1.0}_{-0.8}). Our result is consistent with predictions from both our SAM mock clusters and literature's predictions for dark matter haloes. The mock sample predictions rise slowly with decreasing redshift reaching cg=6.30.36+0.39c_{g}=6.3^{+0.39}_{-0.36} at z=0.Comment: 17 pages, 3 tables, 12 Figures. Accepted for publications in MNRAS. Version 2: modified Figs. 4, 8 and 1

    Quantum correlations between two distant cavity QED systems coupled by a mechanical resonator

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    Achieving quantum correlations between two distant systems is a desirable feature for quantum networking. In this work, we study a system composed of two quantum emitter-cavity subsystems spatially separated. A mechanical resonator couples to either both quantum emitters or both cavities leading to quantum correlations between both subsystems such as non-local light-matter dressed states and cavity-cavity normal mode splitting. These indirect couplings can be explained by an effective Hamiltonian for large energy detuning between the mechanical resonator and the atoms/cavities. Moreover, it is found optimal conditions for the physical parameters of the system in order to maximize the entanglement of such phonon-mediated couplings
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