Transport Properties of Solitons

We calculate in this article the transport coefficients which characterize the dynamics of solitons in quantum field theory using the methods of dissipative quantum systems. We show how the damping and diffusion coefficients of soliton-like excitations can be calculated using the integral functional formalism. The model obtained in this article has new features which cannot be obtained in the standard models of dissipation in quantum mechanics.Comment: 16 Pages, RevTeX, Preprint UIU

Doped planar quantum antiferromagnets with striped phases

We study the properties of the striped phases that have been proposed for the doped cuprate planar quantum antiferromagnets. We invoke an effective, spatially anisotropic, non-linear sigma model in two space dimensions. Our theoretical predictions are in {\it quantitative} agreement with recent experiments. We focus on (i) the staggered magnetization at $T=0$ and (ii) the N\'eel temperature, as functions of doping; these have been measured recently in La${}_{2-x}$ Sr${}_x$ Cu O${}_4$ with $0 \leq x \leq 0.018$. Good agreement with experiment is obtained using parameters determined previously and independently for this system. These results support the proposal that the low doping (antiferromagnetic) phase of the cuprates has a striped configuration.Comment: 4 pages, RevteX, 2 figures, new references added, minor changes in wording and corrections of some formula

Comment on "BCS superconductivity of Dirac fermions in graphene layers"

Comment on "BCS superconductivity of Dirac fermions in graphene layers" by N. B. Kopnin and E. B. Sonin [arXiv:0803.3772; Phys. Rev. Lett. 100, 246808 (2008)].Comment: 1.1 page