Prof. Dr. Thomas Voigtmann im Theoriekolloquium

Prof. Dr. Thomas Voigtmann from Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft und Raumfahrt on Scaling laws for aging in glasses

Scaling laws for aging in glasses

Glasses are out-of-equilibrium materials and thus prone to aging effects: produced by a rapid quench in thermodynamic control parameter(s), the dynamics of the system is characterized by a slow structural relaxation dynamics whoe time scale τ continues to evolve and grows with increasing waiting time after the quench. As a result, a glass is a material that encodes its production history, and its properties are not just quantified by the thermodynamic control parameters only.

The age-dependent evolution after a quench is an example of a non-equilibrium transient process whose full description in terms of statistical mechanics remains elusive. I will discuss how under certain assumptions the integration-through-transients (ITT) framework combined with a mode-coupling theory (MCT) closure allows to predict scaling laws for the evolution of the relaxation time τ after a quench. These encompass regimes of "normal aging" (τ grows linear with age), "hyper-aging" (τ grows faster than the system age) and a "sub-aging" crossover (τ increases slower than the age). They describe computer-simulation results quantitatively. Further, the inclusion of non-mean-field-like fluctuations through a recent extension of MCT explains that hyper-aging is cut off at long times.

[1] T. Rizzo and Th. Voigtmann, Qualitative features at the glass crossover, EPL 111, 56008 (2015); Solvable Models of Supercooled Liquids in Three Dimensions, Physical Review Letters 124, 195501 (2020).

[2] L. F. Elizondo-Aguilera et al, Arrested dynamics of the dipolar hard sphere model, Soft Matter 16, 170 (2020).

[3] R. Peredo-Ortiz, M. Medina-Noyola, Th. Voigtmann, and L. F. Elizondo-Aguilera, "Inner clocks" of glass-forming liquids, Journal of Chemical Physics, in press (2022); DOI:10.1063/5.0087649