Aging as dynamics in configuration space
نویسندگان
چکیده
The relaxation dynamics of many disordered systems, such as structural glasses, proteins, granular materials or spin glasses, is not completely frozen even at very low temperatures [1,2]. This residual motion leads to a change of the properties of the material, a process commonly called aging. Despite recent advances in the theoretical description of such aging processes, the microscopic mechanisms leading to the aging dynamics are still a matter of dispute [3–5]. In this letter we investigate the aging dynamics of a simple glass former by means of molecular dynamics computer simulation. Using the concept of the inherent structure we give evidence that aging dynamics can be understood as a decrease of the effective configurational temperature T of the system. From our results we conclude that the equilibration process is faster when the system is quenched to Tc, the critical T of mode-coupling theory [6], and that thermodynamic concepts [7,8] are useful to describe the out-of-equilibrium aging process. Despite their constitutive differences, many complex disordered materials show a strikingly similar dynamical behavior [1,9]. In such systems, the characteristic relaxation time increases by many decades upon a small variation of the external control parameters such as T or density. Correlation functions show power-law and stretched exponential behavior as opposed to a simple exponential decay. Also the equilibration process is frequently of
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