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NEWS

Dr Ulf Bissbort

Massachusetts Institute of Technology, Department of Nuclear Science and Engineering (MA, USA)

Wednesday, March 5th, 2014 at 04:30:00 PM

Conference Room Querzoli LENS

Published on-line at 12:13:44 PM on Tuesday, February 25th, 2014

Quasi-Particle Theory for the Higgs Amplitude Mode

I will present and discuss a generalized quasi-particle theory for bosonic lattice systems, which naturally contains all relevant collective modes, including th

I will present and discuss a generalized quasi-particle theory for bosonic lattice systems, which naturally contains all relevant collective modes, including the Higgs amplitude in the strongly correlated superfluid. In contrast to Bogoliubov theory, this non-perturbative method does not rely on a small condensate depletion and is valid for any interaction strength in three spatial dimensions. It is based on an expansion around the bosonic Gutzwiller ground state in terms of appropriately chosen fluctuation operators and lays the foundation for the description of real-time dynamics in terms of the natural, weakly interacting quasi-particles. Furthermore, it provides a systematic framework for efficiently calculating observables beyond the Gutzwiller approximation and for including external perturbations, as well as higher order decay and interactions in terms of quasi-particle operators. It allows for the construction of an alternative path integral approach in terms of quasi-particle coherent states.

For further informations, please contact Dr Nicole Fabbri.