Huge (but finite) time scales in slow relaxations: beyond simple aging
  Experiments performed in the last years demonstrated slow relaxations and aging in the conductance of a large variety of materials. Here, we present experimental and theoretical results for conductance relaxation and aging for the case-study example of porous silicon. The relaxations are experimentally observed even at room temperature over timescales of hours, and when a strong electric field is applied for a time $t_w$, the ensuing relaxation depends on $t_w$. We derive a theoretical curve and show that all experimental data collapse onto it with a single timescale as a fitting parameter. This timescale is found to be of the order of thousands of seconds at room temperature. The generic theory suggested is not fine-tuned to porous silicon, and thus we believe the results should be universal, and the presented method should be applicable for many other systems manifesting memory and other glassy effects. 
Ariel Amir, Stefano Borini, Yuval Oreg and Yoseph Imry
cond-mat.dis-nn cond-mat.mes-hall cond-mat.mtrl-sci cond-mat.stat-mech cond-mat.str-el