  We investigate the zero-temperature properties of a quasi-ideal Fermi gas
with Rashba spin-orbit coupling. We find that the spin-orbit term strongly
affects the speeds of zero sound and first sound in the Fermi gas, due to the
presence of a third-order quantum phase transition. In addition, including a 2D
harmonic confinement we show that also the shape of the density profile of the
cloud crucially depends on the strength of the Rashba coupling.
