2008/01/31 by Ralf Schützhold, Michael Uhlmann, Uwe R. Fischer
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Physics of Superconductivity and Magnetism #Quantum, superfluid, helium dynamics #cond-mat.other
paper · pdf · doi:10.1103/physreva.78.033604
published as Phys. Rev. A 78, 033604 (2008) · 5 pages of RevTex4; as published in Physical Review A
openalex publication_date 2008/09/08 · arxiv created 2008/09/09 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We derive a controlled expansion into mean field plus fluctuations for the extended Bose-Hubbard model, involving interactions with many neighbors on an arbitrary periodic lattice, and study the superfluid-supersolid phase transition. Near the critical point, the impact of (thermal and quantum) fluctuations on top of the mean field grows, which entails striking effects, such as negative superfluid densities and thermodynamical instability of the superfluid phase---earlier as expected from mean-field dynamics. We also predict the existence of long-lived ``supercooled'' states with anomalously large quantum fluctuations.