The Perturbative Spectrum of the Dressed Sliver

We analyze the fluctuations of the dressed sliver solution found in a previous paper, hep-th/0311198, in the operator formulation of Vacuum String Field Theory. We derive the tachyon wave function and then analyze the higher level fluctuations. We show that the dressing is responsible for implementing the transversality condition on the massless vector. In order to consistently deal with the singular $k=0$ mode we introduce a string midpoint regulator and we show that it is possible to accommodate all the open string states among the solutions to the linearized equations of motion. We finally show how the dressing can give rise to the correct ratio between the energy density of the dressed sliver and the brane tension computed via the three-tachyons-coupling.Comment: 52 pages, v2: comment added in sec. 5, v3: one appendix added, comments added in introduction and conclusion, to appear on PR

Boundary states as exact solutions of (vacuum) closed string field theory

We show that the boundary states are idempotent B*B=B with respect to the star product of HIKKO type closed string field theory. Variations around the boundary state correctly reproduce the open string spectrum with the gauge symmetry. We explicitly demonstrate it for the tachyonic and massless vector modes. The idempotency relation may be regarded as the equation of motion of closed string field theory at a possible vacuum.Comment: 30 pages, 2 figures, v3:regularization improve

Stochastic Hamiltonian for Non-Critical String Field Theories from Double-Scaled Matrix Models

We present detailed discussions on the stochastic Hamiltonians for non-critical string field theories on the basis of matrix models. Beginning from the simplest $c=0$ case, we derive the explicit forms of the Hamiltonians for the higher critical case $k=3$ (which corresponds to $c=-22/5$) and for the case $c=1/2$, directly from the double-scaled matrix models. In particular, for the two-matrix case, we do not put any restrictions on the spin configurations of the string fields. The properties of the resulting infinite algebras of Schwinger-Dyson operators associated with the Hamiltonians and the derivation of the Virasoro and $W_3$ algebras therefrom are also investigated. Our results suggest certain universal structure of the stochastic Hamiltonians, which might be useful for an attempt towards a background independent string field theory.Comment: 70 pages, LaTeX, typographical errors are corrected, to be published in Phys. Rev.

Winding Number in String Field Theory

Motivated by the similarity between cubic string field theory (CSFT) and the Chern-Simons theory in three dimensions, we study the possibility of interpreting N=(\pi^2/3)\int(U Q_B U^{-1})^3 as a kind of winding number in CSFT taking quantized values. In particular, we focus on the expression of N as the integration of a BRST-exact quantity, N=\int Q_B A, which vanishes identically in naive treatments. For realizing non-trivial N, we need a regularization for divergences from the zero eigenvalue of the operator K in the KBc algebra. This regularization must at same time violate the BRST-exactness of the integrand of N. By adopting the regularization of shifting K by a positive infinitesimal, we obtain the desired value N[(U_tv)^{\pm 1}]=\mp 1 for U_tv corresponding to the tachyon vacuum. However, we find that N[(U_tv)^{\pm 2}] differs from \mp 2, the value expected from the additive law of N. This result may be understood from the fact that \Psi=U Q_B U^{-1} with U=(U_tv)^{\pm 2} does not satisfy the CSFT EOM in the strong sense and hence is not truly a pure-gauge in our regularization.Comment: 20 pages, no figures; v2: references added, minor change

Holographic Construction of Technicolor Theory

We construct a dual description of technicolor theory based on the D4/D8 brane configuration. A strongly-coupled technicolor theory is identified as the effective theory on D-branes, and from the gauge/gravity correspondence, we explore the weakly-coupled holographic description of dynamical electroweak symmetry breaking. It is found from the D-brane probe action that the masses of W and Z bosons are given by the decay constant of technipion, and the technimesons become hierarchically heavy. Moreover, the couplings of heavier modes to standard model fermions are rather suppressed. The oblique correction parameters are also evaluated and found to be small except for the S parameter, which can be reduced by modifying the model. The fermion fields are introduced at the intersections of D-branes and their masses are generated via massive gauge bosons from open strings stretching between D-branes.Comment: 23 pages; references added, minor change

Physics potentials of pp and pep solar neutrino fluxes

Experimental determinations of the pp and pep fluxes have great potentialities. We briefly review the reasons that make such measurements privileged tests of neutrino properties. We discuss the predictions for these fluxes given by four good solutions to the solar neutrino problem: small- and large-angle MSW and Just-So oscillations into active neutrinos, and small-angle MSW oscillations into sterile neutrinos. In addition, we examine the impact of the planned Hellaz detector, which should measure separately the nu_e and nu_mu fluxes in the pp energy window and the signal from the pep neutrinos, for distinguishing among the different solutions and for determining the solar central temperature.Comment: 14 pages, ReVTeX, plus 9 postscript figure

Conformal Symmetry and A New Gauge in the Matrix Model

We generalize the background gauge in the Matrix model to propose a new gauge which is useful for discussing the conformal symmetry. In this gauge, the special conformal transformation (SCT) as the isometry of the near-horizon geometry of the D-particle solution is directly reproduced with the correct coefficient as the quantum correction to the SCT in the Matrix model. We also present a general argument for the relation between the gauge choice and the field redefinition in the Matrix model.Comment: 17 pages, LaTeX, no figures; v2: Introduction modified, references added and typos corrected; v3: Introduction changed; v4: Eq.(12) corrected; v5: final version to appear in Phys. Rev.

Holographic QCD and Pion Mass

To realize massive pions, we study variations of the holographic model of massless QCD using the D4/D8/anti-D8 brane configuration proposed by Sakai and Sugimoto. We propose deformations which break the chiral symmetry explicitly and compute the mass of the pions and vector mesons. The observed value of the pion mass can be obtained. We also argue a chiral perturbation corresponding to our deformation.Comment: 23pages, minor changes, references adde

Synchronization of uncoupled oscillators by common gamma impulses: from phase locking to noise-induced synchronization

Nonlinear oscillators can mutually synchronize when they are driven by common external impulses. Two important scenarios are (i) synchronization resulting from phase locking of each oscillator to regular periodic impulses and (ii) noise-induced synchronization caused by Poisson random impulses, but their difference has not been fully quantified. Here we analyze a pair of uncoupled oscillators subject to common random impulses with gamma-distributed intervals, which can be smoothly interpolated between regular periodic and random Poisson impulses. Their dynamics are charac- terized by phase distributions, frequency detuning, Lyapunov exponents, and information-theoretic measures, which clearly reveal the differences between the two synchronization scenarios.Comment: 18 page

Probability of a Solution to the Solar Neutrino Problem Within the Minimal Standard Model

Tests, independent of any solar model, can be made of whether solar neutrino experiments are consistent with the minimal Standard Model (stable, massless neutrinos). If the experimental uncertainties are correctly estimated and the sun is generating energy by light-element fusion in quasi-static equilibrium, the probability of a standard-physics solution is less than 2%. Even when the luminosity constraint is abandoned, the probability is not more than 4%. The sensitivity of the conclusions to input parameters is explored.Comment: PRL, Revtex, 1 figure, 5 page