AMO Seminar - David Petrosyan: Correlations of Rydberg excitations in optically driven atomic ensembles
Info about event
Title: Correlations of Rydberg excitations in optically driven atomic ensembles
Speaker: David Petrosyan, Institute of Electronic Structure & Laser, Heraklion
Time and place: Thursday 28/11, 15:15, Phys. Aud.
I will discuss resonant optical excitation of Rydberg states of atoms in the presence of relaxations. Atoms in high-lying Rydberg states strongly interact with each other via long-range potentials [1,2]. These interactions translate into the level shifts of multiple Rydberg excitations which are therefore strongly suppressed. Collection of atoms within a certain "blockade" volume can then accommodate at most a single Rydberg excitation [3,4].
Perhaps counterintuitively, dephasing of atomic polarization increases the steady-state excitation probability of such a Rydberg "superatom". Larger atomic ensembles can accommodate more Rydberg excitations which effectively repel each other. The Rydberg superatoms behave as soft spheres resulting in highly sub-Poissonian probability distribution of the number of excitations. In the finite size one- and two-dimensional systems, the boundary effects mediate quasi-crystallization of Rydberg excitations , while the density-density correlations exhibit damped spatial oscillations.
Similar to a single superatom, dephasing and larger atom density lead to stronger density-density correlations of Rydberg excitations .
 T.F. Gallagher, Rydberg Atoms (Cambridge University Press, Cambridge, 1994)  M. Saffman, T.G. Walker, K. Molmer, Rev. Mod. Phys. 82, 2313 (2010)  M.D. Lukin et al., Phys. Rev. Lett. 87, 037901 (2001)  Y.O. Dudin, L. Li, F. Bariani, and A. Kuzmich, Nature Phys. 8, 790
 P. Schauss et al., Nature 491, 87 (2012)  D. Petrosyan, J. Phys. B 46, 141001 (2013); Phys. Rev. A 88, 043431 (2013); Phys. Rev. A 87, 053414 (2013).
Coffee, tea and cake will be served at 15:05.
Annette Svendsen, Jacob Sherson and Aurelien Dantan