Hydrodynamics of3He-A in high magnetic fields

Abstract

The hydrodynamic theory of 3He-A in high magnetic fields is presented. The authors obtain various novel predictions unique for 3He-A in high magnetic fields. Among these they find that the derivative of the spin order parameter transforms under Galilei invariance neither like a velocity nor like a Galilei invariant quantity. In addition the authors obtain a reversible current coupling the spin order parameter and the density, which reflects the fact that gauge invariance is broken spontaneously by the spin order parameter and they are led to the conclusion that a 'four-fluid' hydrodynamics is most appropriate for the description of 3He-A in high magnetic fields. Furthermore, a reversible static coupling of magnetic field, pressure and temperature is predicted leading to a 'magnetic fountain' effect and to a 'magnetothermal' effect.