$\mathbb{Z}_2$ phases and Majorana spectroscopy in paired Bose-Hubbard chains

Autor: Vishveshwara, Smitha, Weld, David M.
Rok vydání: 2020
Předmět:
Druh dokumentu: Working Paper
DOI: 10.1103/PhysRevA.103.L051301
Popis: We investigate the Bose-Hubbard chain in the presence of nearest-neighbor pairing. The pairing term gives rise to an unusual gapped $\mathbb{Z}_2$ Ising phase that has number fluctuation but no off-diagonal long range order. This phase has a strongly correlated many-body doubly degenerate ground state which is effectively a gap-protected macroscopic qubit. In the strongly interacting limit, the system can be mapped onto an anisotropic transverse spin chain, which in turn can be mapped to the better-known fermionic sister of the paired Bose-Hubbard chain: the Kitaev chain which hosts zero-energy Majorana bound states. While corresponding phases in the fermionic and bosonic systems have starkly different wavefunctions, they share identical energy spectra. We describe a possible cold-atom realization of the paired Bose-Hubbard model in a biased zig-zag optical lattice with reservoir-induced pairing, opening a possible route towards experimental Kitaev chain spectroscopy.
Comment: 5 pages, 2 figures
Databáze: arXiv