Narrow Results

In this paper, we have studied the transport properties in two-dimensional superconductors in the frame of the Langevin approach to the time dependent Ginzburg–Landau equation. The electrical and thermoelectric conductivity, resulting from thermal fluctuations of the superconducting order parameter, are computed in the self-consistent Gaussian approximation for an arbitrarily strong electric field and a magnetic field. The Nernst signal, describing the Nernst effect in type-II superconductor under a magnetic field, is also calculated in linear response limit. We obtain analytical expressions for the electrical conductivity, the thermoelectric conductivity and the Nernst signal summing all Landau levels without need to cutoff higher Landau levels to treat an arbitrary magnetic field. Our results indicate that the electrical and thermoelectric conductivity are suppressed in high electric fields and the Nernst signal is in good agreement with experimental data on ${\mathrm{\text{Bi}}}_2{\mathrm{\text{Sr}}}_2{\mathrm{\text{CaCu}}}_2{\mathrm{\text{O}}}_{8+\delta }$.

The thermal conductivity of pionic medium has been evaluated with the help of its standard expression from the relaxation time approximation, where inverse of pion relaxation time or pion thermal width has been obtained from the imaginary part of pion self-energy. In the real-time formalism of thermal field theory, the finite temperature calculations of pion self-energy for πσ and πρ loops have been done. The numerical value of our thermal conductivity increases with temperature very softly, though at particular temperature, our estimation has to consider a large band of phenomenological uncertainty.

We have attempted to build a parametric-based simplified and analytical model to map the interaction of quarks and gluons in the presence of magnetic field, which has been constrained by quark condensate and thermodynamical quantities like pressure, energy density, etc., obtained from the calculation of lattice quantum chromodynamics (QCDs). To fulfill that mapping, we have assumed a parametric temperature and magnetic field-dependent degeneracy factor, average energy, momentum and velocity of quarks and gluons. Implementing this QCD interaction in calculation of transport coefficient at finite magnetic field, we have noticed that magnetic field and interaction both are two dominating sources, for which the values of transport coefficients can be reduced. Though the methodology is not so robust, but with the help of its simple parametric expressions, one can get a quick rough estimation of any phenomenological quantity, influenced by temperature and magnetic field-dependent QCD interaction.