Orbital momentum of vortices and textures due to spectral flow through the gap nodes: Example of the 3He-A continuous vortex
The orbital momentum of the axisymmetric textures and vortices in fermi superfluids and superconductors is discussed on the example of 3He-A. If there are no zeroes in the quasiparticle spectrum, the orbital momentum of the texture is robust, ie it is not sensitive to the change of the texture, provided that the axial symmetry is not violated. If zeroes exist or there is an anomalous branch of the low-energy fermions in the vortex core, the orbital momentum depends on texture. This dependence comes from accumulation of the fermionic topological charge induced by the texture. The change of the orbital momentum in texture occurs by spectral flow through the nodes or along the anomalous branch.