Composite Strings in (2+1)-Dimensional Anisotropic Weakly-Coupled Yang-Mills Theory

The small-scale structure of a string connecting a pair of static sources is explored for the weakly-coupled anisotropic SU(2) Yang-Mills theory in (2+1) dimensions. A crucial ingredient in the formulation of the string Hamiltonian is the phenomenon of color smearing of the string constituents. The quark-anti-quark potential is determined. We close with some discussion of the standard, fully Lorentz-invariant Yang-Mills theory.Comment: Some minor errors corrected, references slightly reorganized, version to appear in Phys. Rev.

Confinement in (2+1)-Dimensional Gauge Theories at Weak Coupling

In axial gauge, the (2+1)-dimensional SU($N$) Yang-Mills theory is equivalent to a set of (1+1)-dimensional integrable models with a non-local coupling between charge densities. This fact makes it possible to determine the static potential between charges at weak coupling in an anisotropic version of the theory, and understand features of the spectrum.Comment: Four pages, Based on a talk given at ``Quark Confinement and the Hadron Spectrum 7", Ponta Delgada, Sao Miguel, Azores, Portugal, Sept. 2-7, 200

The universal coefficient of the exact correlator of a large-NN matrix field theory

Exact expressions have been proposed for correlation functions of the large-$N$ (planar) limit of the $(1+1)$-dimensional ${\rm SU}(N)\times {\rm SU}(N)$ principal chiral sigma model. These were obtained with the form-factor bootstrap. The short-distance form of the two-point function of the scaling field $\Phi(x)$, was found to be $N^{-1}\langle {\rm Tr}\,\Phi(0)^{\dagger} \Phi(x)\rangle=C_{2}\ln^{2}mx$, where $m$ is the mass gap, in agreement with the perturbative renormalization group. Here we point out that the universal coefficient $C_{2}$, is proportional to the mean first-passage time of a L\'{e}vy flight in one dimension. This observation enables us to calculate $C_{2}=1/16\pi$.Comment: Text lengthened from 3 to 6 pages, to include discussion of previous results and directions for further work. Some references added. Accepted for publication in Phys. Rev.

Longitudinal Rescaling of Quantum Electrodynamics

We investigate quantum longitudinal rescaling of electrodynamics, transforming coordinates as $x^{0,3}\to\lambda x^{0,3}$ and $x^{1,2}\to x^{1,2}$, to one loop. We do this by an aspherical Wilsonian renormalization, which was applied earlier to pure Yang-Mills theory. We find the anomalous powers of $\lambda$ in the renormalized couplings. Our result is only valid for $\lambda \lesssim 1$, because perturbation theory breaks down for $\lambda \ll 1$.Comment: Version to appear in Phys. Rev.