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August 10
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Aug. 10 - 2a
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9:00 - 9:30
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9:30 - 10:00
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10:00 - 10:30
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| Searching for a supersolid phase in three dimensions |
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Takafumi Suzuki |
| Since the fascinating features of solid helium were presented by torsional oscillator experiments for the solid helium four [1], ordered states on the bosonic lattice models have received a great deal of attention. Recently, the existence of the supersolid phase in the hard-core bosons on the triangular lattice was demonstrated by a numerical calculation [2]. Such bosonic lattices can be experimentally realized by trapping the ultra-cold bosonic atoms into the optical lattices. It is useful to study the ordered states on the bosonic lattice models in order to clarify the characteristics of the supersolid state. In this study, we investigate the ordered states of the hard-core bosons with unfrustrated hopping and nearest-neighbor repulsion on the face-centered cubic (FCC) lattice. The static structure factors and the superfluid density are calculated, using a quantum Monte Carlo method. At the half filling and the three-quarter filling, the ordered phases with the crystalline lattice appear below the critical temperature. However, between the two fillings, there appears the phase in which the long-range diagonal order and the superfluidity coexist. This phase is in contrast to the ordered phases observed for Ising spins [3]. We discuss more details of the supersolid states on the FCC lattice.
[1] E. Kim and M. H. W. Chan, Nature 427, 225 (2004); Science 305, 1941 (2004). |