Bose soft discs: a minimal model for supersolidity

作者：Saccani S; Moroni S^*; Vitali E; Boninsegni M

来源：Molecular Physics, 2011, 109(23-24): 2807-2812.

DOI：10.1080/00268976.2011.615346

• supersolidity
• cluster solid
• Bose gas

The low temperature phase diagram of an assembly of Bose particles, interacting via a simple soft disc potential, is studied numerically by means of Monte Carlo simulations. At sufficiently high densities, the system features a cluster crystal phase, as observed in its classical counterpart. In the low temperature limit, and in a relatively wide region of parameter space, the quantum cluster crystal undergoes a transition to a supersolid phase, displaying both a finite superfluid fraction and crystalline order. We argue that soft-core Bosons ought be regarded as a 'minimal model' of continuous-space supersolidity. With the aim of elucidating the interplay between superfluid response and solid order, we compute the excitation spectrum of the system. A comparison of that of the insulating cluster crystal with that of the supersolid, shows that the latter features an additional acoustic mode.

• 出版日期2011