Coupled-cluster theory for bosons in rings and optical lattices

Ofir E. Alon, Alexej I. Streltsov, Lorenz S. Cederbaum

Research output: Contribution to journalArticlepeer-review


Bosons in optical lattices and rings are attractive and active fields of research in cold-atom physics. Here, we apply our recently developed coupled-cluster approach for bosons in external traps to these systems, and extend it to the lowest-in-energy excited states with total quasi- or angular-momentum k. In the coupled-cluster approach the exact many-boson ground state is obtained by applying an exponential operator exp{T}, T = ∑n = 1N Tn to the ground configuration, which is (usually) the state where the bosons occupy a single orbital. For excited states, a second exponential operator exp{T(k)}, T(k) = ∑n = 1N Tn(k) is employed to accommodate the remaining excitations from the unperturbed excited configuration. Due to the conservation of momentum, T1 and T1(k) can vanish. Working equations for coupled-cluster (singles) doubles (CCD) are provided and their implications are briefly discussed.

Original languageEnglish
Pages (from-to)151-158
Number of pages8
JournalJournal of Molecular Structure: THEOCHEM
Issue number1-3
StatePublished - 4 Jun 2006
Externally publishedYes


  • Bosonic systems
  • Bosons in rings
  • Cold atoms
  • Coupled-cluster
  • Optical lattices

ASJC Scopus subject areas

  • Biochemistry
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry


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