Dresden 2011 – scientific programme

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A: Fachverband Atomphysik

A 25: Ultra-cold plasmas and Rydberg systems I

A 25.3: Talk

Thursday, March 17, 2011, 17:15–17:30, BAR 106

Many-body spin interactions and the ground state of a dense Rydberg lattice gas — •Igor Lesanovsky — University of Nottingham, School of Physics and Astronomy, University Park, Nottingham NG7 2RD, United Kingdom

We study a one-dimensional atomic lattice gas in which Rydberg states are excited by a laser and whose external dynamics is frozen. We identify a parameter regime in which the Hamiltonian is well-approximated by a spin Hamiltonian with quasi-local many-body interactions and possesses an exact analytic ground state solution. This is due to the fact that for certain parameters the Hamiltonian can be approximately written in a so-called stochastic matrix form. The ground state is then a superposition of all states of the system that are compatible with an interaction induced constraint weighted by a fugacity. We perform a detailed analysis of this state which exhibits a cross-over between a paramagnetic phase with short-ranged correlations and a crystal. Moreover, we discuss its entanglement properties and outline an experimental procedure for achieving a maximally entangled state.
[1] I. Lesanovsky, arXiv:1010.2349 (2010)