SAMOP 2023 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 38: Ultra-cold Plasmas and Rydberg Systems I (joint session A/Q)

Q 38.2: Talk

Wednesday, March 8, 2023, 14:45–15:00, F303

Self-Organized Criticality and Griffith's Effects — •Daniel Brady and Michael Fleischhauer — University of Kaiserslautern - Landau, Kaiserslautern, Germany

Rydberg atoms interact strongly over very large distances leading to effects such as blockade and facilitation. Using Monte-Carlo simulations of an optically driven Rydberg many body gas in the facilitation regime, we analyse the effects of disorder on the facilitation dynamics of the system. In the absence of disorder, realised e.g. by the thermal motion of the atoms, the system exhibits a phase transition between an active and an absorbing phase. The presence of an additional slow decay results in self-organized criticality.

In the low temperature limit, dynamics in the gas are entirely determined on a local scale giving rise to a heterogeneous, disordered Griffiths phase. Here, the facilitation dynamics are constrained to clusters where inter-atom distances equal the facilitation distance. The structure of these clusters can be mapped to an Erdos-Renyi graph. We numerically investigate the dynamics and improve an existing Langevin equation to this regime.

Furthermore, since the network structure changes slower than the internal facilitation dynamics in this regime, spatial correlations appear between atoms. We investigate these utilizing a two atom toy model.