Topological dynamics near exceptional points in an optomechanical system

Recently, it was predicted that the energy transfer between normal modes of open systems with a specific type of degeneracy known as an exceptional point (EP) could be achieved by topological operations, and that the outcome of these operations would be non-reciprocal. 1 Here we demonstrate this topological transfer of energy between two vibrational modes of a cryogenic optomechanical device using a tunable laser. We also show the non-reciprocity of the energy transfer process. These results open up new directions in system control, as well as other dynamical processes of multimode systems that are robust against small perturbations.