Characteristics of Cosmic Time

The nature of cosmic time is illuminated using Hamilton-Jacobi theory for general relativity. For problems of interest to cosmology, one may solve for the phase of the wavefunctional by using a line integral in superspace. Each contour of integration corresponds to a particular choice of time hypersurface, and each yields the same answer. In this way, one can construct a covariant formalism where all time hypersurfaces are treated on an equal footing. Using the method of characteristics, explicit solutions for an inflationary epoch with several scalar fields are given. The theoretical predictions of double inflation are compared with recent galaxy data and large angle microwave background anisotropies.Comment: 20 pages, RevTex using Latex 2.09, Submitted to Physical Review D Two figures included in fil

Determination of HQET parameter \lambda_1 from Inclusive Semileptonic B Meson Decay Spectrum

We estimate the heavy quark effective theory parameter \lambda_1 from inclusive semileptonic B-meson decay spectrum. By using recent CLEO double lepton tagging data of B -> X e nu, which shows the lepton momentum as low as 0.6 GeV, we extracted \lambda_1 \sim -0.58 GeV^2. We also derived \bar\Lambda \sim 0.46 GeV and |V_{cb}| = 0.041 \pm 0.002.Comment: 13 pages, 3 figures, LaTeX. Typos are corrected, and added one commen

Particle dynamics in a class of 2-dimensional gravity theories

We provide a method to determine the motion of a classical massive particle in a background geometry of 2-dimensional gravity theories, for which the Birkhoff theorem holds. In particular, we get the particle trajectory in a continuous class of 2-dimensional dilaton gravity theories that includes the Callan-Giddings-Harvey-Strominger (CGHS) model, the Jackiw-Teitelboim (JT) model, and the $d$-dimensional $s$-wave Einstein gravity. The explicit trajectory expressions for these theories are given along with the discussions on the results.Comment: 15 pages, LaTeX. The deletion of the repeated portion of the abstract and the proper line wrapping of the tex file. No other change

Conductivity Due to Classical Phase Fluctuations in a Model For High-T_c Superconductors

We consider the real part of the conductivity, \sigma_1(\omega), arising from classical phase fluctuations in a model for high-T_c superconductors. We show that the frequency integral of that conductivity, \int_0^\infty \sigma_1 d\omega, is non-zero below the superconducting transition temperature $T_c$, provided there is some quenched disorder in the system. Furthermore, for a fixed amount of quenched disorder, this integral at low temperatures is proportional to the zero-temperature superfluid density, in agreement with experiment. We calculate \sigma_1(\omega) explicitly for a model of overdamped phase fluctuations.Comment: 4pages, 2figures, submitted to Phys.Rev.

Inflationary models inducing non-Gaussian metric fluctuations

We construct explicit models of multi-field inflation in which the primordial metric fluctuations do not necessarily obey Gaussian statistics. These models are realizations of mechanisms in which non-Gaussianity is first generated by a light scalar field and then transferred into curvature fluctuations. The probability distribution functions of the metric perturbation at the end of inflation are computed. This provides a guideline for designing strategies to search for non-Gaussian signals in future CMB and large scale structure surveys.Comment: 4 pages, 7 figure

Linear optical implementation of a single mode quantum filter and generation of multi-photon polarization entangled state

We propose a scheme to implement a single-mode quantum filter, which selectively eliminates the one-photon state in a quantum state $\alpha|0>+\beta|1>+\gamma|2>$. The vacuum state and the two photon state are transmitted without any change. This scheme requires single-photon sources, linear optical elements and photon detectors. Furthermore we demonstrate, how this filter can be used to realize a two-qubit projective measurement and to generate multi-photon polarization entangled states.Comment: revision submitted to PR

Decay Constants and Semileptonic Decays of Heavy Mesons in Relativistic Quark Model

We investigate the $B$ and $D$ mesons in the relativistic quark model by applying the variational method with the Gaussian wave function. We calculate the Fermi momentum parameter $p_{_F}$, and obtain $p_{_F} = 0.50 \sim 0.54$ GeV, which is almost independent of the input parameters, $\alpha_s$, $m_b$, $m_c$ and $m_{sp}$. We then calculate the ratio $f_B$/$f_D$, and obtain the result which is larger, by the factor of about 1.3, than $\sqrt{M_D / M_B}$ given by the naive nonrelativistic analogy. This result is in a good agreement with the recent Lattice calculations. We also calculate the ratio $(M_{B^*}-M_{B})$/$(M_{D^*}-M_{D})$. In these calculations the wave function at origin $\psi (0)$ is essential. We also determine $p_{_F}$ by comparing the theoretical prediction of the ACCMM model with the lepton energy spectrum of $B \rightarrow e \nu X$ from the recent ARGUS analysis, and find that $p_{_F}=0.27~\pm~^{0.22}_{0.27}$ GeV, when we use $m_c=1.5$ GeV. However, this experimentally determined value of $p_{_F}$ is strongly dependent on the value of input parameter $m_c$.Comment: 15 pages (Latex) (uses epsfig.sty, 1 figure appended as a uuencoded compressed ps-file

Abelian 2-form gauge theory: superfield formalism

We derive the off-shell nilpotent Becchi-Rouet-Stora-Tyutin (BRST) and anti-BRST symmetry transformations for {\it all} the fields of a free Abelian 2-form gauge theory by exploiting the geometrical superfield approach to BRST formalism. The above four (3 + 1)-dimensional (4D) theory is considered on a (4, 2)-dimensional supermanifold parameterized by the four even spacetime variables x^\mu (with \mu = 0, 1, 2, 3) and a pair of odd Grassmannian variables \theta and \bar\theta (with \theta^2 = \bar\theta^2 = 0, \theta \bar\theta + \bar\theta \theta = 0). One of the salient features of our present investigation is that the above nilpotent (anti-)BRST symmetry transformations turn out to be absolutely anticommuting due to the presence of a Curci-Ferrari (CF) type of restriction. The latter condition emerges due to the application of our present superfield formalism. The actual CF condition, as is well-known, is the hallmark of a 4D non-Abelian 1-form gauge theory. We demonstrate that our present 4D Abelian 2-form gauge theory imbibes some of the key signatures of the 4D non-Abelian 1-form gauge theory. We briefly comment on the generalization of our supperfield approach to the case of Abelian 3-form gauge theory in four (3 + 1)-dimensions of spacetime.Comment: LaTeX file, 23 pages, journal versio

Correlation induced phonon softening in low density coupled bilayer systems

We predict a possible phonon softening instability in strongly correlated coupled semiconductor bilayer systems. By studying the plasmon-phonon coupling in coupled bilayer structures, we find that the renormalized acoustic phonon frequency may be softened at a finite wave vector due to many-body local field corrections, particularly in low density systems where correlation effects are strong. We discuss experimental possibilities to search for this predicted phonon softening phenomenon.Comment: 4 pages with 2 figure

A fitter code for Deep Virtual Compton Scattering and Generalized Parton Distributions

We have developped a fitting code based on the leading-twist handbag Deep Virtual Compton Scattering (DVCS) amplitude in order to extract the Generalized Parton Distributions (GPD) information from DVCS observables in the valence region. In a first stage, with simulations and pseudo-data, we show that the full GPD information can be recovered from experimental data if enough observables are measured. If only part of these observables are measured, valuable information can still be extracted, certain observables being particularly sensitive to certain GPDs. In a second stage, we make a practical application of this code to the recent DVCS Jefferson Lab Hall A data from which we can extract numerical constraints for the two $H$ GPD Compton Form Factors.Comment: 15 pages, 8 figure