Sound waves in solids in magnetic field

In this communication we present a theoretical analysis of sound modes in nonmagnetic solids or fluids in static and uniform magnetic field. The physics behind is based on the so-called gyromagnetic phenomena i.e., the appearance of a magnetic moment due to the intrinsic orbital moment of vibrational modes. The gyromagnetic contributions into the Lagrangian describing vibrations, conceptually dramatically modify the correlation (and linear response) functions of the displacements. Namely, in the response function one gets singular branching points (instead of simple poles which determine sound mode dispersion laws). In practical terms the corrections are very small although X-ray and optic experimental techniques have progressed to the point where observations of such very small effects are not hopeless. Copyright (C) EPLA, 2011