Perturbative out of equilibrium quantum field theory beyond the gradient approximation and generalized Boltzmann equation

Using the closed-time-path formalism, we construct perturbative frameworks, in terms of quasiparticle picture, for studying quasiuniform relativistic quantum field systems near equilibrium and non-equilibrium quasistationary systems. We employ the derivative expansion and take in up to the second-order term, i.e., one-order higher than the gradient approximation. After constructing self-energy resummed propagator, we formulated two kind of mutually equivalent perturbative frameworks: The first one is formulated on the basis of the ``bare'' number density function, and the second one is formulated on the basis of ``physical'' number density function. In the course of construction of the second framework, the generalized Boltzmann equations directly come out, which describe the evolution of the system.Comment: LaTeX2e, 20 page

Transport coefficients from QCD Kondo effect

We study the transport coefficients from the QCD Kondo effect in quark matter which contains heavy quarks as impurity particles. We estimate the coupling constant of the interaction between a light quark and a heavy quark at finite density and temperature by using the renormalization group equation up to two-loop order. We also estimate the coupling constant at zero temperature by using the mean-field approximation as non-perturbative treatment. To calculate the transport coefficients, we use the relativistic Boltzmann equation and apply the relaxation time approximation. We calculate the electric resistivity from the relativistic kinetic theory, and the viscosities from the relativistic hydrodynamics. We find that the electric resistivity is enhanced and the shear viscosity is suppressed due to the QCD Kondo effect at low temperature.Comment: 20 pages, 8 figure

Fermi/non-Fermi mixing in SU(NN) Kondo effect

We apply conformal field theory analysis to the $k$-channel SU($N$) Kondo system, and find a peculiar behavior in the cases $N > k > 1$, which we call Fermi/non-Fermi mixing: The low temperature scaling is described as the Fermi liquid, while the zero temperature IR fixed point exhibits the non-Fermi liquid signature. We also show that the Wilson ratio is no longer universal for the cases $N > k > 1$. The deviation from the universal value of the Wilson ratio could be used as an experimental signal of the Fermi/non-Fermi mixing.Comment: 24 pages, no figures; minor changes, ref. added; typos correcte

On Local Symmetric Order Parameters of Vortex Lattice States

This paper gives a new refined definition of local symmetric order parameters (OPs)(s-wave, d-wave and p-wave order parameters) of vortex lattice states for singlet superconductivity. s-wave, d-wave and p-wave OPs at a site (m,n) are defined as A, B and E representations of the four fold rotation C_4 at the site (m,n) of nearest neighbor OPs etc. The new OPs have a well defined nature such that an OP(e.g. d-wave) at the site obtained under translation by a lattice vector (of the vortex lattice) from a site (m,n) is expressed by the corresponding OP (e.g. d-wave) at the site (m,n) times a phase factor. The winding numbers of s-wave and d-wave OPs are given.Comment: RevTeX v3.1, 5 pages with 3 figures, uses epsf.sty. to appear in Prog. Theor. Phys. Vol.101 No.3. (1999