The exact three-dimensional half-shell t-matrix for a sharply cut-off Coulomb potential in the screening limit

The three-dimensional half-shell t-matrix for a sharply cut-off Coulomb potential is analytically derived together with its asymptotic form without reference to partial wave expansion. The numerical solutions of the three-dimensional Lippmann-Schwinger equation for increasing cut-off radii provide half-shell t-matrices which are in quite a good agreement with the asymptotic values.Comment: 15 pages, 4 eps figure

Synergistic warm inflation

We consider an alternative warm inflationary scenario in which $n$ scalar fields coupled to a dissipative matter fluid cooperate to produce power--law inflation. The scalar fields are driven by an exponential potential and the bulk dissipative pressure coefficient is linear in the expansion rate. We find that the entropy of the fluid attains its asymptotic value in a characteristic time proportional to the square of the number of fields. This scenario remains nearly isothermal along the inflationary stage. The perturbations in energy density and entropy are studied in the long--wavelength regime and seen to grow roughly as the square of the scale factor. They are shown to be compatible with COBE measurements of the fluctuations in temperature of the CMB.Comment: 13 pages, Revtex 3 To be published in Physical Review

Coarse-Grained Finite-Temperature Theory for the Condensate in Optical Lattices

In this work, we derive a coarse-grained finite-temperature theory for a Bose condensate in a one-dimensional optical lattice, in addition to a confining harmonic trap potential. We start from a two-particle irreducible (2PI) effective action on the Schwinger-Keldysh closed-time contour path. In principle, this action involves all information of equilibrium and non-equilibrium properties of the condensate and noncondensate atoms. By assuming an ansatz for the variational function, i.e., the condensate order parameter in an effective action, we derive a coarse-grained effective action, which describes the dynamics on the length scale much longer than a lattice constant. Using the variational principle, coarse-grained equations of motion for the condensate variables are obtained. These equations include a dissipative term due to collisions between condensate and noncondensate atoms, as well as noncondensate mean-field. To illustrate the usefulness of our formalism, we discuss a Landau instability of the condensate in optical lattices by using the coarse-grained generalized Gross-Pitaevskii hydrodynamics. We found that the collisional damping rate due to collisions between the condensate and noncondensate atoms changes sign when the condensate velocity exceeds a renormalized sound velocity, leading to a Landau instability consistent with the Landau criterion. Our results in this work give an insight into the microscopic origin of the Landau instability.Comment: 38 pages, 2 figures. Submitted to Journal of Low Temperature Physic

Intramuscular Olanzapine and Intramuscular Haloperidol in Acute Schizophrenia: Antipsychotic Efficacy and Extrapyramidal Safety During the First 24 Hours of Treatment

To determine the antipsychotic efficacy and extrapyramidal safety of intramuscular (IM) olanzapine and IM haloperidol during the first 24 hours of treatment of acute schizophrenia. Method: Patients (n = 311) with acute schizophrenia were randomly allocated (2:2: 1) to receive IM olanzapine (10.0 mg, n = 131), IM haloperidol (7.5 mg, n = 126), or IM placebo (n = 54). Results: After the first injection, IM olanzapine was comparable to IM haloperidol and superior to IM placebo for reducing mean change scores from baseline on the Brief Psychiatric Rating Scale (BRPS) Positive at 2 hours (-2.9 olanzapine, -2.7 haloperidol, and -1.5 placebo) and 24 hours (-2.8 olanzapine, -3.2 haloperidol, and -1.3 placebo); the BPRS Total at 2 hours (-14.2 olanzapine,-13.1 haloperidol, and -7.1 placebo) and 24 hours (-12.8 olanzapine, -12.9 haloperidol, and -6.2 placebo); and the Clinical Global Impressions (CGI) scale at 24 hours (-0.5 olanzapine, -0.5 haloperidol, and -0.1 placebo). Patients treated with IM olanzapine had significantly fewer incidences of treatment-emergent parkinsonism (4.3% olanzapine vs 13.3% haloperidol, P = 0.036), but not akathisia (1.1% olanzapine vs 6.5% haloperidol, P = 0.065), than did patients treated with IM haloperidol; they also required significantly less anticholinergic treatment (4.6% olanzapine vs 20.6% haloperidol, P < 0.001). Mean extrapyramidal symptoms (EPS) safety scores improved significantly from baseline during IM olanzapine treatment, compared with a general worsening during IM haloperidol treatment (Simpson-Angus Scale total score mean change: -0.61 olanzapine vs 0.70 haloperidol; P < 0.001; Barnes Akathisia Scale global score mean change: -0.27 olanzapine vs 0.01 haloperidol; P < 0.05). Conclusion: IM olanzapine was comparable to IM haloperidol for reducing the symptoms of acute schizophrenia during the first 24 hours of treatment, the efficacy of both being evident within 2 hours after the first injection. In general, more EPS were observed during treatment with IM haloperidol than with IM olanzapine

The clustering instability of inertial particles spatial distribution in turbulent flows

A theory of clustering of inertial particles advected by a turbulent velocity field caused by an instability of their spatial distribution is suggested. The reason for the clustering instability is a combined effect of the particles inertia and a finite correlation time of the velocity field. The crucial parameter for the clustering instability is a size of the particles. The critical size is estimated for a strong clustering (with a finite fraction of particles in clusters) associated with the growth of the mean absolute value of the particles number density and for a weak clustering associated with the growth of the second and higher moments. A new concept of compressibility of the turbulent diffusion tensor caused by a finite correlation time of an incompressible velocity field is introduced. In this model of the velocity field, the field of Lagrangian trajectories is not divergence-free. A mechanism of saturation of the clustering instability associated with the particles collisions in the clusters is suggested. Applications of the analyzed effects to the dynamics of droplets in the turbulent atmosphere are discussed. An estimated nonlinear level of the saturation of the droplets number density in clouds exceeds by the orders of magnitude their mean number density. The critical size of cloud droplets required for clusters formation is more than $20 \mu$m.Comment: REVTeX 4, 15 pages, 2 figures(included), PRE submitte

Detection Limits for Super-Hubble Suppression of Causal Fluctuations

We investigate to what extent future microwave background experiments might be able to detect a suppression of fluctuation power on large scales in flat and open universe models. Such suppression would arise if fluctuations are generated by causal processes, and a measurement of a small suppression scale would be problematic for inflation models, but consistent with many defect models. More speculatively, a measurement of a suppression scale of the order of the present Hubble radius could provide independent evidence for a fine-tuned inflation model leading to a low-density universe. We find that, depending on the primordial power spectrum, a suppression scale modestly larger than the visible Horizon can be detected, but that the detectability drops very rapidly with increasing scale. For models with two periods of inflation, there is essentially no possibility of detecting a causal suppression scale.Comment: 8 pages, 4 figures, revtex, In Press Physical Review D 200

Scalar perturbation spectra from warm inflation

We present a numerical integration of the cosmological scalar perturbation equations in warm inflation. The initial conditions are provided by a discussion of the thermal fluctuations of an inflaton field and thermal radiation using a combination of thermal field theory and thermodynamics. The perturbation equations include the effects of a damping coefficient $\Gamma$ and a thermodynamic potential $V$. We give an analytic expression for the spectral index of scalar fluctuations in terms of a new slow-roll parameter constructed from $\Gamma$. A series of toy models, inspired by spontaneous symmetry breaking and a known form of the damping coefficient, lead to a spectrum with $n_s>1$ on large scales and $n_s<1$ on small scales.Comment: 12 pages, 5 figures, RevTeX 4, revised with extra figure

Purcell enhancement of a deterministically coupled quantum dot in an SU-8 laser patterned photonic crystal heterostructure

Enhancement of single photon source emission through cavity quantum electrodynamics is key to the realization of applicable emitters in many quantum optics technologies. In this work, we present a flexible and convenient cavity fabrication process that writes a SU-8 microstrip onto a photonic crystal waveguide deterministically, in which InGaAs/GaAs quantum dots are present as emitters. The strip cavity is laser patterned at the location of a quantum dot with a chosen emission wavelength. Micro-photoluminescence studies are undertaken, which demonstrate an enhanced emission intensity by a factor of 2.1 with weak coupling to a single quantum dot, and time-resolved photoluminescence further shows a Purcell enhancement factor of 2.16. The fabrication process is, thus, verified as a reliable recipe to introduce deterministic cavity coupling to a chosen quantum dot

Chandra X-ray observations of the 3C295 cluster core

We examine the properties of the X-ray gas in the central regions of the distant (z=0.46), X-ray luminous cluster of galaxies surrounding the powerful radio source 3C 295, using observations made with the Chandra Observatory. Between radii of 50-500 kpc, the cluster gas is approximately isothermal with an emission-weighted temperature, kT ~5 keV. Within the central 50 kpc radius this value drops to kT ~3.7 keV. The spectral and imaging Chandra data indicate the presence of a cooling flow within the central 50 kpc radius of the cluster, with a mass deposition rate of approximately 280 solar masses per year. We estimate an age for the cooling flow of 1-2 Gyr, which is approximately one thousand times older than the central radio source. We find no evidence in the X-ray spectra or images for significant heating of the X-ray gas by the radio source. We report the detection of an edge-like absorption feature in the spectrum for the central 50 kpc region, which may be due to oxygen-enriched dust grains. The implied mass in metals seen in absorption could have been accumulated by the cooling flow over its lifetime. Combining the results on the X-ray gas density profile with radio measurements of the Faraday rotation measure in 3C295, we estimate the magnetic field strength in the region of the cluster core to be B ~12 \muG.Comment: 27 pages, 16 figs, 5 tables. Accepted for publication in MNRA