Three strongly correlated charged bosons in a one-dimensional harmonic   trap: natural orbital occupancies
  We study a one-dimensional system composed of three charged bosons confined in an external harmonic potential. More precisely, we investigate the ground-state correlation properties of the system, paying particular attention to the strong-interaction limit. We explain for the first time the nature of the degeneracies appearing in this limit in the spectrum of the reduced density matrix. An explicit representation of the asymptotic natural orbitals and their occupancies is given in terms of some integral equations. 
Przemyslaw Koscik
quant-ph cond-mat.str-el physics.atm-clus