Francesco Ginelli — Department of Physics and SUPA and ICSMB - King's College - University of Aberdeen (UK) #
Evidence of an absorbing-phase transition in stochastic, long-delayed dynamics #
It is well known that complex dynamical evolution may originate from simple, low-dimensional dynamical systems when a time-delayed feedback mechanism is considered. These may typically happen in systems where the propagation time of a signal is not negligible with respect to the typical timescale of the local dynamics. Examples include laser physics, where a long delayed feedback may be easily obtained by optical or electronic devices. In these systems, a deep analogy exists between delayed feedback and spatially extended dynamical systems. In particular,  it is well known that deterministic systems with long time-delay may be interpreted in terms of a suitable spatiotemporal dynamics.
In this work, we extend this interpretation to stochastic, time delayed dynamics. In particular, we consider a simple bistable system with long delay, and perturb it with a multiplicative noise that preserves one of the two minima.
Comparing experimental data — obtained from a  bistable semiconductor laser with long delay — with numerical simulations of a simple effective model, we argue that these systems exhibit a non-equilibrium phase transition into an absorbing state, possibly belonging to the well known Directed Percolation universality class.