Many-body physics with highly excited atoms
Dr. Igor Lesanovsky (School of Physics and Astromomy The University of Nottingham)

During the past years the relatively new field of ultra cold atomic physics has produced valuable insights into the structure and dynamics of many-body quantum systems. The reason for this success story is rooted in the versatility offered by ultra cold atom systems, such as the tunability of their interactions and the advanced techniques that have been developed for their trapping and coherent manipulation [1].

<p>At present the majority of ultra cold atoms experiments is carried out with ground state atoms. Since very recently, however, there is a growing initiative towards exploiting the unique properties of atoms in highly excited states [2]. These so-called Rydberg atoms are blessed with remarkable properties such as strong interactions and long coherence times. The interactions severely influence the excitation dynamics of dense atomic gases through a mechanism which is called the Rydberg blockade [3]: The large interaction induced energy shift makes it virtually impossible to excite two nearby atoms simultaneously to the Rydberg state, i.e. the presence of one excited atom blocks the excitation of atoms in its vicinity.

<p>I outline how this mechanism can be used to create entangled quantum states [4] and non-classical light sources.
Moreover, I will talk about how a dense Rydberg gas allows to gain insights into the behavior of stronlgy correlated and isolated quantum systems [5].

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[1] I. Bloch, J. Dalibard, and W. Zwerger, Rev. Mod. Phys. 80, 885 (2008)

[2] M. Saffman, T. G. Walker, and K. Molmer, Rev. Mod. Phys.
82, 2313 (2010)

[3] D. Jaksch, J. I. Cirac, P. Zoller, S. L. Rolston, R. Cote, and M. D. Lukin, Phys. Rev. Lett. 85, 2208 (2000)

[4] I. Lesanovsky, Phys. Rev. Lett. 106, 025301 (2011)

[5] I. Lesanovsky, B. Olmos, and J. P. Garrahan, Phys. Rev.
Lett. 105, 100603 (2010)