#### Condensed Matter Theory

### Bettina Gertjerenken et.al.: Trojan quasiparticles

**Author(s)**:**Bettina Gertjerenken, Martin Holthaus****Title**:**Date of Upload**: 2014-09-08
**Article**:**New Journal of Physics 16, 093009 (2014) , Institute of Physics****Keywords**: Bose-Einstein condensates, semiclassical approximations, collective many-body excitations, nonequilibrium quantum dynamics**PACS**: 03.75.Lm;03.75.Kk;05.45.Mt;05.30.Jp;03.65.Sq**Abstract**:- We argue that a time-periodically driven bosonic Josephson junction supports stable, quasiparticle-like collective response modes which are N-particle analogs of the nonspreading Trojan wave packets known from microwave-driven Rydberg atoms. Similar to their single-particle counterparts, these collective modes, dubbed 'flotons', are well described by a Floquet-Mathieu approximation, and possess a well-defined discrete set of excitations. In contrast to other,'chaotic' modes of response, the nonheating Trojan modes conform to a mean-field description, and thus may be of particular interest for the more general question under which conditions the reduction of quantum N-particle dynamics to a strongly simplified mean-field evolution is feasible. Our reasoning is supported by phase-space portraits which reveal the degree of correspondence beween the N-particle dynamics und the mean-field picture in an intuitive manner.
**URL: http://www.physik.uni-oldenburg.de/condmat/Papers/p_Trojan2014.pdf (text/plain)**

**Trojan quasiparticles**

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