Ground state and excitation properties of soft-core bosons
  We study the physics of soft-core bosons at zero temperature in two dimensions for a class of potentials that could be realised in experiments with Rydberg dressed Bose-Einstein condensates. We analyze the ground state properties of the system in detail and provide a complete description of the excitation spectra in both superfluid, supersolid and crystalline phase for a wide range of interaction strengths and densities. In addition we describe a method to extract the transverse gapless excitation modes in the phases with broken translational symmetry within the framework of path integral Monte Carlo methods. 
Tommaso Macri, Sebastiano Saccani and Fabio Cinti
cond-mat.quant-gas