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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 |ψ WM of N identical Gaussian orbitals centred at variationally determined sites, and (ii) a permanent |ψ SM of N orthogonal orbitals built from harmonic-oscillator energy eigenstates. With increasing coupling strength, the bosons in the |ψ WM orbitals localize into polygonal-ringlike crystalline patterns ('Wigner molecules'), whereas the wavefunctions |ψ 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.

ABSTRA CT -The design and operation technique for a stable capacitance control in piezoelectric RF MEMS tunable capacitors have been investigated. Four folded-beam capacitors composed of piezoelectric aluminum nitride thin films were integrated in the quadruple capacitor and each folded-beam capacitor showed uniform operation voltage of less than 3V. A stable multi-step capacitance control was realized with the binary voltage operation at +/-3V, where each capacitor could be handled at binary state of capacitance due to its saturation characteristics. Eight levels of capacitance value up to 1.5pF with a step of O.13pF to O.16pF were realized.