## Strongly Interacting Rydberg Atoms

2008-06-28

Normal version

Rydberg atoms are
atoms with a large principle quantum number. One possibility to create
them is to excite ground state atoms with lasers. They are very
sensitive to electric fields, so if you bring them close together they
will experience very strong interactions due to static or induced
electric dipoles.

We have now put a paper onto
the arXiv, where we investigate the properties of the strongly
interacting regime. We have found some interesting links between
Rydberg physics and concepts originally coming from condensed matter
physics.

For the strongly interacting regime we have shown that exciting
Rydberg atoms with lasers results in quantum critical behavior. In a
nutshell, this means that physical quantities behave independent of
the microscopic details, no matter whether the atoms form a thermal
gas, a Bose-Einstein condensate or sit on a lattice. The reason for
this is that such a driven Rydberg system is close to a second order
quantum phase
transition,
where critical behavior can be expected. Nevertheless the underlying
physics are quite simple: all you need to do is to shine with lasers
on atoms.

**Reference:** H. Weimer, R. Löw, T. Pfau, H. P. Büchler.
Quantum critical behavior in strongly interacting Rydberg
gases * Phys. Rev. Lett.* **101**, 250601
(2008).

arXiv:0806.3754

Copyright 2006--2011 Hendrik Weimer. This document is available under
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