Quantum Hall effect on the Lobachevsky plane
The Hall conductivity of an electron gas on the surface of constant negative curvature (the Lobachevsky plane) in the presence of an orthogonal magnetic field is investigated. It is shown that the surface curvature decreases the quantum Hall plateau widths and shifts the steps in the Hall conductivity to higher magnetic fields (or to lower values of the chemical potential). An increase of temperature results in smearing of the steps.
The main objective of this article is to study dynamic of the ::: three-dimensional Boussinesq equations with the periodic boundary ::: condition.We prove that when the Rayleigh number $R$ crosses the ::: first critical Rayleigh number $R_c$, the Rayleigh-Benard problem ::: bifurcates from the basic state to an global attractor $\Sigma$, which is homeomorphic to $S^3$.