The Coriolis force in rotating solids changes the sound wave dispersion. The equations for the propagation of sound are solved for a rotating isotropic elastic medium and the effects of rotation on the wave dispersion are analyzed.

The interaction of the center of mass motion and the relative motion in a hydrogen atom in crossed electric and magnetic fields leads to peculiar quasi-ionized states with an electron localized very far from a proton. The properties of the state, specifically softening of the proton cyclotron resonance, are discussed.

The symmetry analysis of hypothetical anyonic states in HTSC is performed. A peculiar magnetoelectric state is singled out and its symmetry related optical and static properties are discussed.

High Tc superconductivity has brought to the light an old controversy between band structure and highly correlated description of poor conductors. In band structure approach everything is transparent: We start with nice free electrons and switching on interaction gradually we only have to look what will happen. It is more or less a simple mathematical problem. In highly correlated case the main trouble lies at the very threshold. In fact we still do not know what a Mott insulator is. Last year Anderson put the question in its most natural form: What are excitations of a non-antiferromagnetic Mott insulator with an odd number of bare electrons in the unit cell? Are they neutral fermions, perhaps?

We discuss sources of neutral fermions in paramagnetic insulators which apparently play a major role in high-Tc superconductivity