Three-dimensional spin–orbit coupled Fermi gases: Fulde–Ferrell pairing, Majorana fermions, Weyl fermions, and gapless topological superfluidity*
Liu Xia-Jia), Hu Huia), Pu Hanb),c)†
       
Contour plots of the particle branch E 2+( k ) in (a) the gapped FF phase, (b) the gapped topo-FF4 phase, (c) the gapless topo-FF4 phase, and (d) the gapless topo-FF2 phase. The Weyl nodes are highlighted by yellow solid circles. We note that the in-plane and out-of-plane Zeeman fields are equal, h in = h out = h . The spectrum is symmetric with respect to k y , so we plot only the left part with ky ≤ 0.