Predicted signatures of $p$-wave superfluid phases and Majorana zero modes of fermionic atoms in rf absorption

We study the superfluid phases of quasi-two-dimensional atomic Fermi gases interacting via a $p$-wave Feshbach resonance. We calculate the absorption spectra of these phases under a hyperfine transition for both nonrotating and rotating superfluids. We show that one can identify the different phases of the $p$-wave superfluid from the absorption spectrum. The absorption spectrum shows clear signatures of the existence of Majorana zero modes at the cores of vortices of the weakly pairing $p_x+i{p}_y$ phase.

Figure 1

Peak distribution associated with the Majorana modes on the vortices of the weak-pairing $p_x+i{p}_y$ phase. The first peak will be at $\omega \simeq E_g-\mu$, and other peaks will follow at spacings ${\omega }_c$ apart. Continuous absorption will be measured starting at $\omega \simeq E_g$. For the opposite sense of rotation, the weight of the peaks starts linearly and passes through a maximum. The inset shows the shape of a single peak for a square (dashed line) and triangular (solid line) lattice, calculated for convenience for $T\ll t$, showing a Van Hove singularity at $\omega =2t$ ($\Gamma$ is measured in units of $2\pi \mid \eta {\mid }^2{N}_V{\Theta }_0∕t$).