Photoconduction and photocontrolled collective effects in the Peierls conductor TaS3_3

Light illumination of thin crystals of CDW conductor TaS$_3$ is found to result in dramatic changes of both linear ($G$) and nonlinear conduction. The increase of $G$ is accompanied by suppression of the collective conduction, growth of the threshold field $E_T$, and appearance of the switching and hysteretic behavior in the nonlinear conduction. The effects in the nonlinear conduction are associated with increase of CDW elasticity due to illumination that leads in particular to appearance of a relation $E_T\propto G^{1/3}$ expected for the one-dimensional pinning.Comment: RevTeX4, 4 pages, 4 postscript figures. Revised manuscript, new title, new Fig. 1, text corrections. Journal reference adde

Liquid Nonlinear Oscillations in the U-Tube System

Dynamics of oscillation processes in a siphon U-tube is studied for the system of connected vessels filled with homogeneous liquid. The equations and phase paths describing the motion of viscous and non-viscous liquids are given, oscillation frequencies are considered. Oscillations are nonlinear in general case, but they turn into linear by setting specific parameter values of the system. Phase portraits are obtained and their dependences on parameters of the system are analyzedfor both linear and non-linear cases

Convective Term and Transversely Driven Charge-Density Waves

We derive the convective terms in the damping which determine the structure of the moving charge-density wave (CDW), and study the effect of a current flowing transverse to conducting chains on the CDW dynamics along the chains. In contrast to a recent prediction we find that the effect is orders of magnitude smaller, and that contributions from transverse currents of electron- and hole-like quasiparticles to the force exerted on the CDW along the chains act in the opposite directions. We discuss recent experimental verification of the effect and demonstrate experimentally that geometry effects might mimic the transverse current effect.Comment: RevTeX, 9 pages, 1 figure, accepted for publications in PR