Bonn 2025 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 10: Poster – Ultra-cold Plasmas and Rydberg Systems (joint session A/Q)

A 10.2: Poster

Dienstag, 11. März 2025, 14:00–16:00, Tent

Avalanche events and universality crossover on a dynamical network in a driven, dissipative Rydberg gas — •Simon Ohler, Daniel Brady, and Michael Fleischhauer — RPTU Kaiserslautern-Landau, Germany

In an off-resonantly laser-driven gas of Rydberg atoms, it is known that there exists an absorbing-state phase transition. In the spreading phase the gas is saturated with Rydberg excitations, whereas in the absorbing phase Rydberg excitations stay isolated. At the critical point separating the two, which is the attractor of the dynamics via the self-organized criticality (SOC) mechanism, one can observe scale-free avalanche events where a single Rydberg seed excitations leads to a cascade effect. We numerically investigate the response of a critical gas of atoms under such a minimal perturbation and observe a scale-free avalanche-response irrespective of the thermal motion of the gas. Determining the exponents of power-law avalanche distributions we confirm that the universality class of the associated absorbing-state phase transition changes as a function of temperature. Additionally, we consider the emerging network structure that determines the dynamics and quantify the degree to which this excitation graph is dynamical.

Keywords: Rydberg; avalanches; self-organized criticality; universality; network