Z2 phases and Majorana spectroscopy in paired Bose-Hubbard chains

Smitha Vishveshwara, David M. Weld

Research output: Contribution to journalArticlepeer-review

Abstract

We investigate the Bose-Hubbard chain in the presence of nearest-neighbor pairing. The pairing term gives rise to an unusual gapped Z2 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 wave functions, they share identical energy spectra. We describe a possible cold-atom realization of the paired Bose-Hubbard model in a biased zigzag optical lattice with reservoir-induced pairing, opening a possible route towards experimental Kitaev chain spectroscopy.

Original languageEnglish (US)
Article numberL051301
JournalPhysical Review A
Volume103
Issue number5
DOIs
StatePublished - May 2021
Externally publishedYes

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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