Based on quantum hydrodynamics theory (QHD), the propagation of nonlinear quantum dust-ion acoustic (QDIA) solitary waves in a ‎collision-less, unmagnetized four component quantum plasma consisting of electrons, positrons, ions and stationary negatively charged ‎dust grains with dust charge variation is investigated using reductive perturbation method. The charging current to the dust grains ca...

A bilayer electron system that is formed in a 60-nm-wide GaAs quantum well and has large difference of the densities layers been studied. It found that, when magnetic field tilted from normal to plane system, integer Hall effect states at filling factors Landau levels 1 2 disappear; instead, fractional interval between these appear ν F = 4/3, 10/7, 6/5 with odd denominators factor 5/4. Several ...