Generation of Curvature Perturbations with Extra Anisotropic Stress

We study the evolution of curvature perturbations and the cosmic microwave background (CMB) power spectrum in the presence of an hypothesized extra anisotropic stress which might arise, for example, from the dark radiation term in brane-world cosmology. We evolve the scalar modes of such perturbations before and after neutrino decoupling and analyze their effects on the CMB spectrum. A novel result of this work is that the cancellation of the neutrino and extra anisotropic stress could lead to a spectrum of residual curvature perturbations which is similar to the observed CMB power spectrum. This implies a possible additional consideration in the determination of cosmological parameters from the CMB analysis.Comment: 13 pages, 2 figures; improved discussio

Uq(sl^n)U_q(\hat{sl}_n)-analog of the XXZ chain with a boundary

We study $U_q(\hat{sl}_n)$ analog of the XXZ spin chain with a boundary magnetic field h. We construct explicit bosonic formulas of the vacuum vector and the dual vacuum vector with a boundary magnetic field. We derive integral formulas of the correlation functions.Comment: 24 pages, LaTEX2

Influence of pure-dephasing by phonons on exciton-photon interfaces: Quantum microscopic theory

We have developed a full quantum microscopic theory to analyze the time evolution of transversal and longitudinal components of an exciton-single photon system coupled to bulk acoustic phonons. These components are subjected to two decay processes. One is radiative relaxation and the other is pure-dephasing due to exciton-phonon interaction. The former results in a decay with an exponent linear to time, while the latter causes a faster initial decay than the radiative decay. We analyzed the dependence of the components on the duration of the input one-photon pulse, temperature, and radiative relaxation rates. Such a quantitative analysis is important for the developments of atom-photon interfaces which enable coherent transfer of quantum information between photons and atomic systems. We found that, for a GaAs spherical quantum dot in which the exciton interacts with bulk phonons, the maximal probability of the excited state can be increased up to 75 %. This probability can be considered as the efficiency for quantum information transfer from photon to exciton.Comment: 9pages, 5figure

Spin Fluid Dynamics Observed by Magnetic Fountain Effect and Mechano-Spin Effect in the Ferromagnetic Superfluid 3^3He A1_1 Phase

Systematic observations of the magnetically generated fountain pressure in the superfluid $^3$He A$_1$ have been carried out in a newly built apparatus designed to reduce the effect of thermal gradients. In the same apparatus, mechanical pumping and filtering of polarized nuclear spins were realized by the pneumatic pumping action of an electrostatically actuated membrane. In both experiments, the measured induced pressure was observed to decay at all temperatures where the A$_1$ phase appeared in magnetic fields up to 13 T and liquid pressures between 1 and 29 bar. The inferred spin relaxation rate tended to increase as the low temperature phase boundary with the A$_2$ phase (T$_{C2}$) was approached. The increase in spin relaxation rate near T$_{C2}$ can be explained by the presence of a minority spin condensate in the A$_1$ phase as predicted by Monien and Tewordt and by the application of the Leggett-Takagi theory of spin relaxation in superfluid $^3$He.Comment: 12 pages, 15 figures, to appear in Physical Review

The Long-Short Story of Movie Description

Generating descriptions for videos has many applications including assisting blind people and human-robot interaction. The recent advances in image captioning as well as the release of large-scale movie description datasets such as MPII Movie Description allow to study this task in more depth. Many of the proposed methods for image captioning rely on pre-trained object classifier CNNs and Long-Short Term Memory recurrent networks (LSTMs) for generating descriptions. While image description focuses on objects, we argue that it is important to distinguish verbs, objects, and places in the challenging setting of movie description. In this work we show how to learn robust visual classifiers from the weak annotations of the sentence descriptions. Based on these visual classifiers we learn how to generate a description using an LSTM. We explore different design choices to build and train the LSTM and achieve the best performance to date on the challenging MPII-MD dataset. We compare and analyze our approach and prior work along various dimensions to better understand the key challenges of the movie description task

The Riemann-Hilbert problem associated with the quantum Nonlinear Schrodinger equation

We consider the dynamical correlation functions of the quantum Nonlinear Schrodinger equation. In a previous paper we found that the dynamical correlation functions can be described by the vacuum expectation value of an operator-valued Fredholm determinant. In this paper we show that a Riemann-Hilbert problem can be associated with this Fredholm determinant. This Riemann-Hilbert problem formulation permits us to write down completely integrable equations for the Fredholm determinant and to perform an asymptotic analysis for the correlation function.Comment: 21 pages, Latex, no figure

Annihilation poles of a Smirnov-type integral formula for solutions to quantum Knizhnik--Zamolodchikov equation

We consider the recently obtained integral representation of quantum Knizhnik-Zamolodchikov equation of level 0. We obtain the condition for the integral kernel such that these solutions satisfy three axioms for form factor \'{a} la Smirnov. We discuss the relation between this integral representation and the form factor of XXZ spin chain.Comment: 14 pages, latex, no figures

Integral equations for the correlation functions of the quantum one-dimensional Bose gas

The large time and long distance behavior of the temperature correlation functions of the quantum one-dimensional Bose gas is considered. We obtain integral equations, which solutions describe the asymptotics. These equations are closely related to the thermodynamic Bethe Ansatz equations. In the low temperature limit the solutions of these equations are given in terms of observables of the model.Comment: 22 pages, Latex, no figure

Direct CP, T and/or CPT violations in the K^0-\bar{K^0} system - Implications of the recent KTeV results on 2π2\pi decays -

The recent results on the CP violating parameters Re(e'/e) and \Delta\phi = \phi_{00}-\phi_{+-} reported by the KTeV Collaboration are analyzed with a view to constrain CP, T and CPT violations in a decay process. Combining with some relevant data compiled by the Particle Data Group, we find Re(e_2-e_0) = (0.85 +- 3.11)*10^{-4} and Im(e_2-e_0) = (3.2 +- 0.7)*10^{-4}, where Re(e_I) and Im(e_I) represent respectively CP/CPT and CP/T violations in decay of K^0 and \bar{K^0} into a 2\pi state with isospin I.Comment: 7 pages, No figure