Stable Topological Superfluid Phase of Ultracold Polar Fermionic Molecules

We show that single-component fermionic polar molecules confined to a 2D geometry and dressed by a microwave field may acquire an attractive $1/r^3$ dipole-dipole interaction leading to superfluid $p$-wave pairing at sufficiently low temperatures even in the BCS regime. The emerging state is the topological $p_x+i{p}_y$ phase promising for topologically protected quantum information processing. The main decay channel is via collisional transitions to dressed states with lower energies and is rather slow, setting a lifetime of the order of seconds at 2D densities $\sim {10}^8{\mathrm{cm}}^{-2}$.

Figure 1

Potential energy curve $V_0(r)$ for two $|+⟩$ state molecules, computed for ${\Omega }_R=0.25\delta$ (see text). Anticrossings with other field-dressed levels of even parity occur at distances $r\sim r_{\delta }$, as shown in the inset.

Figure 2

Inelastic rate constant $\alpha$ as a function of $r_{\delta }/{\lambda }_{\delta }$ for ${\Omega }_R=0.25\delta$ and $k{r}^{*}=1$ (see text).