Using a generalized two-fluid pictures for the charge of superconductor and ordinary Boltzmann equation for quasiparticle excitations, the effect of frequency and wave-vector dependent electromagnetic perturbation on charge imbalance near transition temperatureT_C is studied. In a situatiod where both the effective charge and distribution function of quasiparticles deviate from their equilibrium values, the charge imbalance is shown to possess a propagating solution at frequencies greater than inelastic scattering rate. In situations where charge imbalance is created by injection of quasiparticles, the charge imbalance relaxation rate is shown to decrease. We also study the effect of applied perturbation on quasiparticle diffusion length and hence on superconductor—normal interface boundary resistance.

Using a generalised two-fluid picture for the charge of a superconductor, the generation of charge imbalance by a temperature gradient under different conditions is studied. The voltage developed by a temperature gradient in the presence of supercurrent is estimated. The results agree with experiment. The results obtained for the generation of charge imbalance in the absence of imposed current agree with those obtained using other techniques.

The current-voltage characteristics of a quasi one-dimensional organic system having asymmetric donor molecule like Qn-(TCNQ)₂ pellet with stoichiometry 1:2 grown from acetonitrile as a solvent have been studied atT=69 K. The characteristic curves show a pronounced deviation from ohmicity beyond a certain value of current. For higher values of currents a negative differential resistance region is observed.

We address the problem of classical frictional motion under a potentialV possessing a barrier, apart from other possible confining and nonstationary terms. It is pointed out that the Green’s solution of the exact equation of motion can be reduced (under suitable conditions) either to an improved Rayleigh form or a non-Rayleigh form, the latter being outside the scope of the standard large-friction treatment of the Fokker-Planck equation. The resulting dissipationless dynamics involves an appropriately scaled potential which may have promising applications to quantum stochastic phenomena. Genuine dissipative corrections in regions far away from the barrier can be accounted for by the higher-order terms in our asymptotic expansions.