Soliton-induced Majorana fermions in a one-dimensional atomic topological superfluid

Abstract

We theoretically investigate the behavior of dark solitons in a one-dimensional spin-orbit coupled atomic Fermi gas in harmonic traps, by solving self-consistently the Bogoliubov-de Gennes equations. The dark soliton - to be created by phase-imprinting in future experiments - is characterized by a real order parameter, which changes sign at a point node and hosts localized Andreev bound states near the node. By considering both cases of a single soliton and of multiple solitons, we find that the energy of these bound states decreases to zero, when the system is tuned to enter the topological superfluid phase by increasing an external Zeeman field. As a result, two Majorana fermions emerge in the vicinity of each soliton, in addition to the well-known Majorana fermions at the trap edges associated with the nontrivial topology of the superfluid. We propose that the soliton-induced Majorana fermions can be directly observed by using spatially-resolved radio-frequency spectroscopy or indirectly probed by measuring the density profile at the point node. For the latter, the deep minimum in the density profile will disappear due to the occupation of the soliton-induced zero-energy Majorana fermion modes. Our prediction could be tested in a resonantly-interacting spin-orbit coupled ${}^{40}$K Fermi gas confined in a two-dimensional optical lattice.

9 pages, 8 figures

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Cited by in corpus (10)

• On controlling the bound states in quantum-dot hybrid-nanowire
• Dynamic structure factor of one-dimensional Fermi superfluid with spin-orbit coupling
• Dynamical generation of solitons in one-dimensional Fermi superfluids with and without spin-orbit coupling
• Two types of dark solitons in a spin-orbit-coupled Fermi gas
• Coexistence of topological and nontopological Fermi-superfluid phases
• Dynamic structure factor of two-dimensional Fermi superfluid with Rashba spin-orbit coupling
• A universal pairing gap measurement proposal by dynamical excitations in 2D doped attractive Fermi-Hubbard model with spin-orbit coupling
• Engineering Majorana Kramers Pairs In Synthetic High Spin Chern Insulators
• Finding the stable mechanism of ring solitons in two-dimensional Fermi superfluids
• Majorana bound states in the presence of the half-smeared potential