The encoding of rejuvenation and memory effects in hierarchical energy landscapes

The slow relaxation of disordered systems known as aging exhibits puzzling behavior when subjected to temperature shifts, leading to the rejuvenation effect, for example. When these effects are realized in mean field spin glasses, they are attributed to the hierarchical energy landscape of the spin glasses, a consequence of replica symmetry breaking (RSB). Here, we give a counterexample to demonstrate that, while hierarchical landscapes do produce rejuvenation effects, the dynamics are not necessarily governed by RSB. We introduce a toy model, the cluster model, developed based on the idea that aging is governed by record dynamics (RD)[1] in which rare events of record size allow a system to overcome energetic or entropic barriers, before reconfiguring into the next metastable state. Our numerical simulations of the cluster model show that even with the absence of RSB, the system still produces rejuvenation and memory effects. These effects can be explained with the timescales of the rare events as a reflection of the topology of the landscape.


[1] N. Becker et al 2014 J. Phys.: Condens. Matter 26 505102
https://doi.org/10.1088/0953-8984/26/50/505102