  Glass-forming liquids exhibit a dramatic dynamical slowdown as the
temperature is lowered. This can be attributed to relaxation proceeding via
large structural rearrangements whose characteristic size increases as the
system cools. These cooperative rearrangements are well modeled by instantons
in a replica effective field theory, with the size of the dominant instanton
encoding the liquid's cavity point-to-set correlation length. Varying the
parameters of the effective theory corresponds to varying the statistics of the
underlying free-energy landscape. We demonstrate that, for a wide range of
parameters, replica-symmetry-breaking instantons dominate. The detailed
structure of the dominant instanton provides a rich window into point-to-set
correlations and glassy dynamics.
