Confinement in Gauge Theories from the Condensation of World-Sheet Defects in Liouville String

We present a Liouville-string approach to confinement in four-dimensional gauge theories, which extends previous approaches to include non-conformal theories. We consider Liouville field theory on world sheets whose boundaries are the Wilson loops of gauge theory, which exhibit vortex and spike defects. We show that world-sheet vortex condensation occurs when the Wilson loop is embedded in four target space-time dimensions, and show that this corresponds to the condensation of gauge magnetic monopoles in target space. We also show that vortex condensation generates a effective string tension corresponding to the confinement of electric degrees of freedom. The tension is independent of the string length in a gauge theory whose electric coupling varies logarithmically with the length scale. The Liouville field is naturally interpreted as an extra target dimension, with an anti-de-Sitter (AdS) structure induced by recoil effects on the gauge monopoles, interpreted as D branes of the effective string theory. Black holes in the bulk AdS space correspond to world-sheet defects, so that phases of the bulk gravitational system correspond to the different world-sheet phases, and hence to different phases of the four-dimensional gauge theory. Deconfinement is associated with a Berezinskii-Kosterlitz-Thouless transition of vortices on the Wilson-loop world sheet, corresponding in turn to a phase transition of the black holes in the bulk AdS space.Comment: 29 pages LATEX, three eps figures incorporate

An asymptotic formula for marginal running coupling constants and universality of loglog corrections

Given a two-loop beta function for multiple marginal coupling constants, we derive an asymptotic formula for the running coupling constants driven to an infrared fixed point. It can play an important role in universal loglog corrections to physical quantities.Comment: 16 pages; typos fixed, one appendix removed for quick access to the main result; to be published in J. Phys.

Quantum creep and quantum creep transitions in 1D sine-Gordan chains

Discrete sine-Gordon (SG) chains are studied with path-integral molecular dynamics. Chains commensurate with the substrate show the transition from collective quantum creep to pinning at bead masses slightly larger than those predicted from the continuous SG model. Within the creep regime, a field-driven transition from creep to complete depinning is identified. The effects of disorder in the external potential on the chain's dynamics depend on the potential's roughness exponent $H$, i.e., quantum and classical fluctuations affect the current self-correlation functions differently for $H = 1/2$.Comment: 4 pages, 3 figure

Dynamical Chiral Symmetry Breaking on a Brane in Reduced QED

Reduced gauge theories are theories in which while gauge fields propagate in a bulk, fermion fields are localized on a brane. We study dynamical chiral symmetry breaking on a 2-brane and a 1-brane in reduced QED_{3+1}, and on a 1-brane in reduced QED_{2+1}. Since, unlike higher dimensional gauge theories, QED_{3+1} and QED_{2+1} are well defined, their reduced versions can serve as a laboratory for studying dynamics in a higher dimensional brane world. The analysis of the Schwinger-Dyson (SD) equations in these theories reveals rich and quite nontrivial dynamics in which the conformal symmetry and its breakdown play a crucial role. Explicit solutions of the SD equations in the near-critical regime are obtained and the character of the corresponding phase transition is described.Comment: PRD versio

Neutrinos produced by ultrahigh-energy photons at high red shift

Some of the proposed explanations for the origin of ultrahigh-energy cosmic rays invoke new sources of energetic photons (e.g., topological defects, relic particles, etc.). At high red shift, when the cosmic microwave background has a higher temperature but the radio background is low, the ultrahigh-energy photons can generate neutrinos through pair-production of muons and pions. Neutrinos produced at high red shift by slowly evolving sources can be detected. Rapidly evolving sources of photons can be ruled out based on the existing upper limit on the neutrino flux.Comment: 4 pages, revtex; to appear in Phys. Rev. Let

d_{x^2-y^2}-Wave Pairing Fluctuations and Pseudo Spin Gap in Two-Dimensional Electron Systems

Pseudogap phenomena of high-T_c cuprates are examined. In terms of AFM (antiferromagnetic) and dSC (d_{x^2-y^2}-wave superconducting) auxiliary fields introduced to integrate out the fermions, the effective action for 2D electron systems with AFM and dSC fluctuations is considered. By the self-consistent renormalization (SCR), the NMR relaxation rate T_1^{-1}, the spin correlation length \xi_\sigma and the pairing correlation length \xi_d are calculated. From this calculation, a mechanism of the pseudogap formation emerges as the region of dominant d-wave short-range order (SRO) over AFM-SRO. When damping for the AFM fluctuation strongly depends on the dSC correlation length through the formation of precursor singlets around (\pi,0) and (0,\pi) points in the momentum space, the pseudogap appears in a region of the normal state characterized by decreasing 1/T_1T and increasing AFM correlation length with decrease in temperature. This reproduces a characteristic feature of the pseudogap phenomena in many underdoped cuprates. When the damping becomes insensitive to the dSC correlation length, the pseudogap region shrinks as in the overdoped cuprates.Comment: 13 pages with 5 figures, submitted to J. Phys. Soc. Jpn.; figure inclusion correcte