The static lengthscale characterizing the glass transition at lower temperatures

The existence of a static lengthscale that grows in accordance with the dramatic slowing-down observed at the glass transition is a subject of intense interest. Due to limitations on the relaxation times reachable by standard molecular-dynamics techniques (i.e. a range of about 4-5 orders of magnitude) it was until now impossible to demonstrate a significant enough increase in any proposed lengthscale. In this letter we explore the typical scale at unprecedented lower temperatures. A Swap Monte Carlo approach allows us to reach a lengthscale growth by more than 500%. We conclude by discussing the relationship between the observed lengthscale and various models of the relaxation time, proposing that the associated increase in relaxation time approaches experimental values.