Roton softening and supersolidity in Rb spinor condensates

Understand

Superfluids with a tendency towards periodic crystalline order have both a phonon and roton like spectrum of collective modes.

• The softening of the roton spectrum provides one route to a supersolid.
• We show that roton softening occurs in 87Rb spinor condensates once dipolar interactions and spin dynamics are taken into account.
• By including the effects of a quasi-two-dimensional geometry and rapid Larmor precession, we show a dynamical instability develops in the collective mode spectrum at finite wavevectors.