TY - JOUR
T1 - Majorana fermions in quasi-one-dimensional and higher-dimensional ultracold optical lattices
AU - Qu, Chunlei
AU - Gong, Ming
AU - Xu, Yong
AU - Tewari, Sumanta
AU - Zhang, Chuanwei
N1 - Publisher Copyright:
© 2015 American Physical Society.
PY - 2015/8/14
Y1 - 2015/8/14
N2 - We study Majorana fermions (MFs) in quasi-one dimensional (quasi-1D) and higher-dimensional fermionic optical lattices with a strictly 1D spin-orbit coupling, which has already been realized in cold atom experiments. We show that when the superfluid order parameters are homogeneous and are enforced to be identical along different chains, there are multiple MFs at each end with or without an experimentally tunable in-plane Zeeman field Vy. For Vy=0 the multiple MFs are topologically protected by a chiral symmetry; however, for Vy≠0 the existence of multiple MFs is related to the peculiar spectrum properties of the system despite the broken chiral symmetry. In the generalization to higher dimensions, the multiple MFs form a zero-energy flat band. Furthermore, when the superfluid order parameters are solved self-consistently, the multiple MFs are usually destroyed because of the inhomogeneous order parameters of either Bardeen-Cooper-Schrieffer (Vy=0) type or Fulde-Ferrell (Vy≠0) type. Our results are useful to guide the experimentalists on searching for MFs in ultracold spin-orbit coupled fermionic superfluids.
AB - We study Majorana fermions (MFs) in quasi-one dimensional (quasi-1D) and higher-dimensional fermionic optical lattices with a strictly 1D spin-orbit coupling, which has already been realized in cold atom experiments. We show that when the superfluid order parameters are homogeneous and are enforced to be identical along different chains, there are multiple MFs at each end with or without an experimentally tunable in-plane Zeeman field Vy. For Vy=0 the multiple MFs are topologically protected by a chiral symmetry; however, for Vy≠0 the existence of multiple MFs is related to the peculiar spectrum properties of the system despite the broken chiral symmetry. In the generalization to higher dimensions, the multiple MFs form a zero-energy flat band. Furthermore, when the superfluid order parameters are solved self-consistently, the multiple MFs are usually destroyed because of the inhomogeneous order parameters of either Bardeen-Cooper-Schrieffer (Vy=0) type or Fulde-Ferrell (Vy≠0) type. Our results are useful to guide the experimentalists on searching for MFs in ultracold spin-orbit coupled fermionic superfluids.
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U2 - 10.1103/PhysRevA.92.023621
DO - 10.1103/PhysRevA.92.023621
M3 - Article
AN - SCOPUS:84939429496
SN - 1050-2947
VL - 92
JO - Physical Review A - Atomic, Molecular, and Optical Physics
JF - Physical Review A - Atomic, Molecular, and Optical Physics
IS - 2
M1 - 023621
ER -