Supercooled liquids for pedestrians

By Andrea Cavagna. 2009

708 citations recorded by the source corpus.

When we lower the temperature of a liquid, at some point we meet a first order phase transition to the crystal. Yet, under certain conditions it is possible to keep the system in its metastable phase and to avoid crystallization. In this way the liquid enters in the supercooled phase. Supercooled liquids have a very rich phenomenology, which is still far from being completely understood. To begin with, there is the problem of how to prevent crystallization and how deeply the liquid can be supercooled before a metastability limit is hit. But by far the most interesting feature of supercooled liquids is the dynamic glass transition: when the temperature is decreased below a certain point, the relaxation time increases so much that a dramatic dynamical arrest intervenes and we are unable to equilibrate the system within reasonable experimental times. The glass transition is a phenomenon whose physical origin has stirred an enormous interest in the last hundred years. Why does it occur? Is it just a conventional reference point, or does it have a more profound physical meaning? Is it a purely dynamical event, or the manifestation of a true thermodynamic transition? What is the correlation length associated to the sharp increase of the relaxation time? Can we define a new kind of amorphous order? A shared theory of supercooled liquids and the glass transition does not yet exist and these questions are still largely open. Here, I will illustrate in the most elementary fashion the main phenomenological traits of supercooled liquids and discuss in a very partial way a few theoretical ideas on the subject.

Subfields: Biomedical Engineering, Condensed Matter Physics, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/87ba4cacb0ad1a92da80559ba87af63648e48565

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Citations in the corpus

Fractal free energy landscapes in structural glasses (2014, methodology): “It can be shown that at equilibrium the metabasins entropies on a scale ∆ are independent random variables distributed according to P∆(s) ∝ e [3, 17] , and therefore the typical value of s on a scale ∆ is styp(∆) ∝ 1/y(∆).”
Kinetically Constrained Models (2010, neutral): “…theoretical picture of the glass transition problem (see (Chandler and Garrahan, 2010) for a review) which is quite distinct from other competing theories (Götze and Sjögren, 1992; Debenedetti and Stillinger, 2001; Lubchenko and Wolynes, 2007; Kivelson and Tarjus, 2008; Cavagna, 2009).”
The role of local structure in dynamical arrest (2014, background): “Alternatively, there may be no transition until absolute zero (where in the classical approach we shall pursue, all motion ceases) [37, 78, 81].”
Excitations Are Localized and Relaxation Is Hierarchical in Glass-Forming Liquids (2011, neutral): “It is a picture that appears significantly different than an often invoked structural perspective originating with Adam and Gibbs [13, 14].”
Theoretical perspective on the glass transition and amorphous materials (2010, background): “Reviews dedicated to different aspects of RFOT theory have appeared recently (Lubchenko and Wolynes, 2007; Götze, 2008; Cavagna, 2009; Biroli and Bouchaud, 2009; Mézard and Parisi, 2010).”
Temperature in and out of equilibrium: A review of concepts, tools and attempts (2017, background): “In thesemodels, see [259,260,200]for reviews,macroscopic stresses are related to strains and/or strain rates through empirical formulae inspired by viscoelasticity (e.”
Mean-field theory of hard sphere glasses and jamming (2008, background): “…on the so-called Random First Order Transition (RFOT) theory of glasses, whose theoretical foundations were posed in a series of papers by Kirkpatrick, Thirumalai and Wolynes (Kirkpatrick and Thirumalai, 1987; Kirkpatrick and Wolynes, 1987a), see (Cavagna, 2009) for a detailed and recent review.”
Aspects of non-equilibrium in classical and quantum systems: Slow relaxation and glasses, dynamical large deviations, quantum non-ergodicity, and open quantum dynamics (2017, methodology): “One can argue [21, 38] furthermore that the parabolic law provides a superior fit to the data to that found using the traditional VFT form [1, 2, 3, 4, 5], ln τVFT ∝ (T − TK), without the need to invoke an essential singularity at an unobservable TK > 0.”