Glass transitions may be similar in 2 and 3 dimensions, after all

This is a commentary on two recent experimental papers in PNAS by Vivek et al. and Illing et al. that convincingly address an issue at the junction of two fundamental questions in glass physics: the role of the dimensionality of space on the glass transition and the possible existence of long wavelength fluctuations in two-dimensional amorphous solids.Comment: 3-page Commentar

Random-field-like criticality in glass-forming liquids

We introduce an approach to derive an effective scalar field theory for the glass transition; the fluctuating field is the overlap between equilibrium configurations. We apply it to the case of constrained liquids for which the introduction of a conjugate source to the overlap field was predicted to lead to an equilibrium critical point. We show that the long-distance physics in the vicinity of this critical point is in the same universality class as that of a paradigmatic disordered model: the random-field Ising model. The quenched disorder is provided here by a reference equilibrium liquid configuration. We discuss to what extent this field-theoretical description and the mapping to the random field Ising model hold in the whole supercooled liquid regime, in particular near the glass transition.Comment: 5 pages plus supplementary materia

Decorrelation of the static and dynamic length scales in hard-sphere glass-formers

We show that in the equilibrium phase of glass-forming hard-sphere fluids in three dimensions, the static length scales tentatively associated with the dynamical slowdown and the dynamical length characterizing spatial heterogeneities in the dynamics unambiguously decorrelate. The former grow at a much slower rate than the latter when density increases. This observation is valid for the dynamical range that is accessible to computer simulations, which roughly corresponds to that of colloidal experiments. We also find that in this same range, no one-to-one correspondence between relaxation time and point-to-set correlation length exists. These results point to the coexistence of several relaxation mechanisms in the accessible dynamical regime of three-dimensional hard-sphere glass formers.Comment: 8 pages, 7 figure

Nonperturbative effect of attractive forces in viscous liquids

We study the role of the attractive intermolecular forces in the viscous regime of a simple glass-forming liquid by using computer simulations. To this end, we compare the structure and the dynamics of a standard Lennard-Jones glass-forming liquid model with and without the attractive tail of the interaction potentials. The viscous slowing down of the two systems are found to be quantitatively and qualitatively different over a broad density range, whereas the static pair correlations remain close. The common assumption that the behaviour of dense nonassociated liquids is determined by the short-ranged repulsive part of the intermolecular potentials dramatically breaks down for the relaxation in the viscous liquid regime.Comment: 4 pages, 3 figure