Supplemental Information for : Strain pattern in supercooled liquids

Video microscopy provides access to the full phase space information of the colloidal monolayer at all relevant time and length scales. We record the trajectories of about 2300 colloidal particles (the whole system consists of more than 10 particles) confined to two dimensions by sedimentation at a flat water-air interface. This interface is realized by a water droplet hanging by surface tension in a top-sealed cylindrical hole (6 mm in diameter) of a glass cuvette. The volume and thus the curvature of the droplet is actively regulated by several computer controlled regulation loops to be completely flat for a duration of several months providing excellent long time stability. The species A (diameter σ = 4.5μm) and B (σ = 2.8μm) have a relative concentration of ξ = NB/(NA + NB) ≈ 50 % where NA and NB are the number of particles of both species in the field of view. The binary mixture prevents the system from crystallization. The ratio of the repulsive potential energy versus thermal energy (causing Brownian motion) can be controlled in situ by an external magnetic field H due to the superparamagnetic nature of the particles. It is expressed by the dimensionless system parameter