943 research outputs found

    The origin of scale-scale correlations of the density perturbations during inflation

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    We show that scale-scale correlations are a generic feature of slow-roll inflation theories. These correlations result from the long-time tails characteristic of the time dependent correlations because the long wavelength density perturbation modes are diffusion-like. A relationship between the scale-scale correlations and time-correlations is established providing a way to reveal the time correlations of the perturbations during inflation. This mechanism provides for a testable prediction that the scale-scale correlations at two different spatial points will vanish.Comment: Accepted for publication, International Journal of Modern Physics, vol. 8 No.6 (Dec 1999

    A relativistic calculation of super-Hubble suppression of inflation with thermal dissipation

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    We investigated the evolution of the primordial density perturbations produced by inflation with thermal dissipation. A full relativistic analysis on the evolution of initial perturbations from the warm inflation era to a radiation-dominated universe has been developed. The emphasis is on tracking the ratio between the adiabatic and the isocurvature mode of the initial perturbations. This result is employed to calculate a testable factor: the super-Hubble suppression of the power spectrum of the primordial perturbations. We show that based on the warm inflation scenario, the super-Hubble suppression factor, ss, for an inflation with thermal dissipation is at least 0.5. This prediction does not depend on the details of the model parameters. If ss is larger than 0.5, it implies that the friction parameter Γ\Gamma is larger than the Hubble expansion parameter HH during the inflation era.Comment: 22 pages, 3 figures, use RevTex, accepted by Class. Quant. Gra

    Generalized metarationalities in the graph model for conflict resolution

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    AbstractA metarational tree is defined within the graph model for conflict resolution paradigm, providing a general framework within which rational behavior in models with two decision makers (DMs) can be described more comprehensively. A new definition of stability for a DM that depends on the total number, h, of moves and counter-moves allowed is proposed. Moreover, the metarational tree can be refined so that all moves must be unilateral improvements, resulting in a new set of stability definitions for each level of the tree. Relationships among stabilities at various levels of the basic and refined trees are explored, and connections are established to existing stability definitions including Nash stability, general metarationality, symmetric metarationality, sequential and limited-move stability, and policy equilibria

    Protoplanetary Disks in ρ\rho Ophiuchus as Seen From ALMA

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    We present a high angular resolution (0.2\sim 0.2^{\prime\prime}), high sensitivity (σ0.2\sigma \sim 0.2 mJy) survey of the 870 μ\mum continuum emission from the circumstellar material around 49 pre-main sequence stars in the ρ\rho Ophiuchus molecular cloud. Because most millimeter instruments have resided in the northern hemisphere, this represents the largest high-resolution, millimeter-wave survey of the circumstellar disk content of this cloud. Our survey of 49 systems comprises 63 stars; we detect disks associated with 29 single sources, 11 binaries, 3 triple systems and 4 transition disks. We present flux and radius distributions for these systems; in particular, this is the first presentation of a reasonably complete probability distribution of disk radii at millimeter-wavelengths. We also compare the flux distribution of these protoplanetary disks with that of the disk population of the Taurus-Auriga molecular cloud. We find that disks in binaries are both significantly smaller and have much less flux than their counterparts around isolated stars. We compute truncation calculations on our binary sources and find that these disks are too small to have been affected by tidal truncation and posit some explanations for this. Lastly, our survey found 3 candidate gapped disks, one of which is a newly identified transition disk with no signature of a dip in infrared excess in extant observations.Comment: 26 pages, 16 figures. Accepted for publication in Ap

    Theory of control of optomechanical transducers for quantum networks

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    We present a scheme of control for the arbitrary optical interface mediated by a nanoscale mechanical oscillator between flying qubits and optical nonactive solid-state qubits. This quantum interface lays the foundation for many key functions of a quantum network, such as transferring, swapping, and entangling qubits between distant nodes of a quantum network. Numerical simulations of the quantum interface operations show high fidelities and robust tolerance under realistic experimental conditions. Compared with a previous scheme, it may significantly increase the speed of state transfer operation of high fidelity

    Limit theorems for delayed sums of random sequence

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    Environmental Effect on the Associations of Background Quasars with Foreground Objects: II. Numerical Simulations

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    Using numerical simulations of cluster formation in the standard CDM model (SCDM) and in a low-density, flat CDM model with a cosmological constant (LCDM), we investigate the gravitational lensing explanation for the reported associations between background quasars and foreground clusters. Under the thin-lens approximation and the unaffected background hypothesis , we show that the recently detected quasar overdensity around clusters of galaxies on scales of 10\sim10 arcminutes cannot be interpreted as a result of the gravitational lensing by cluster matter and/or by their environmental and projected matter along the line of sight, which is consistent with the analytical result based on the observed cluster and galaxy correlations (Wu, et al. 1996). It appears very unlikely that uncertainties in the modeling of the gravitational lensing can account for the disagreement between the theoretical predictions and the observations. We conclude that either the detected signal of the quasar-cluster associations is a statistical fluke or the associations are are generated by mechanisms other than the magnification bias.Comment: 15 pages, 5 figures, accepted for publication in Ap
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