Coulomb crystallites from harmonically confined charged bosons in two dimensions

Mese A. I., Capuzzi P., Akdeniz Z., Okan S. E., Tosi M. P.

JOURNAL OF PHYSICS-CONDENSED MATTER, vol.20, no.33, 2008 (SCI-Expanded) identifier identifier


We exploit rotational-symmetry breaking in the one-body density to examine the formation of structures in systems of N strongly coupled charged bosons with logarithmic repulsions inside isotropic two-dimensional harmonic traps, with N in the range from 2 to 7. The results serve as a map for ordered arrangements of vortices in a trapped Bose-Einstein condensate. Two types of N-body wavefunctions are assumed: (i) a permanent vertical bar psi(WM)> of N identical Gaussian orbitals centred at variationally determined sites, and (ii) a permanent vertical bar psi(SM)> of N orthogonal orbitals built from harmonic-oscillator energy eigenstates. With increasing coupling strength, the bosons in the vertical bar psi(WM)> orbitals localize into polygonal-ringlike crystalline patterns ('Wigner molecules'), whereas the wavefunctions vertical bar psi(SM)> describe low energy excited states containing delocalized bosons as in supersolid crystallites ('supermolecules'). For N = 2 at strong coupling both states describe a Wigner dimer.