Hannover 2013 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 26: Ultra-cold atoms, ions and BEC III (with A)

Q 26.5: Talk

Tuesday, March 19, 2013, 12:00–12:15, B 302

Excitation spectrum of supersolids with soft-core bosons — •Tommaso Macri, Fabio Cinti, Fabian Maucher, and Thomas Pohl — Max Planck Institute for the Physics of Complex Systems, Dresden, Germany

Motivated by recent experimental efforts to realize quantum phases of matter with cold atomic Rydberg gases, I will discuss the excitation spectrum of supersolids in a two dimensional bosonic system with soft-core interactions. Previous works showed an exceptional agreement between Monte Carlo simulations and a numerical mean-field approach.

I will present a variational analysis of the Gross-Pitaevskii equation with a non-local interaction term and show that we can quantitatively reproduce the superfluid-supersolid transition at finite interaction strength in agreement with Monte Carlo results. We then test the validity of this mean-field analysis perturbing the ground state wave function and looking at the spectrum of the corresponding Bogoliubov equations. This approach provides an intuitive physical insight to the low energy dynamics of the system and is validated through the comparison of our findings with recent Monte Carlo simulations.