  Hydrodynamic theory of the spinor BEC condensate with Rashba spin-orbit
coupling is presented. A close mathematical analogy of the Rashba-BEC model to
the recently developed theory of chiral magnetism is found. Hydrodynamic
equations for mass density, superfluid velocity, and the local magnetization
are derived. The mass current is shown to contain an extra term proportional to
the magnetization direction, as a result of the Rashba coupling. Elementary
excitations around the two known ground states of the Rashba-BEC Hamiltonian,
the plane-wave and the stripe states, are worked out in the hydrodynamic
framework, highlighting the cross-coupling of spin and superflow velocity
excitations due to the Rashba term.
