Slow Light in Cold Rydberg Gases
August 30, 2012 - 8:00am
The recent advance in coherently controlling and manipulating strong, long-range Rydberg interactions has triggered extensive research in studying interesting many-body effects as, e.g. the use of Rydberg blockade effects for quantum information processing and crystal formation. In this talk I show that Rydberg interactions can be used to alter the photon statistics of a weak probe field after propagating in a coherently prepared atomic Rydberg gas under conditions of Electromagnetically Induced Transparency (EIT).
The Rydberg blockade mechanism leads to an effective two-level physics when two photons are separated by less than the blockade radius resulting in a strong anti-correlation of two photons given by an avoided volume. For large separations the repulsive long-range interaction between the Rydberg atoms induces repulsive interactions between the photons leading to quasi-crystalline states of photons. Confining the system to one dimension the low-energy physics of the excitations can be described in terms of a Luttinger Liquid.
Using DMRG simulations the Luttinger K-parameter is calculated and conditions on the formation of long-range ordered states are derived. Implications of the formation of such hard-sphere photons for the recent experiment of Pritchard et al. [Phys. Rev. Lett. 105, 193603 (2010)] and the observation of long-range correlations in future experiments will be discussed.