Asymmetric balance in symmetry breaking

Bruno Garbin, Julien Fatome, Gian-Luca Oppo, Miro Erkintalo, Stuart G. Murdoch, Stéphane Coen

Published 2019-04-15Version 1

Spontaneous symmetry breaking is central to our understanding of physics and explains many natural phenomena, from cosmic scales to sub-atomic particles. It can also be exploited for applications, but engineered systems naturally present some deviations from perfect symmetry. Surprisingly, the impact of such asymmetries has barely been studied. Here, we experimentally study spontaneous symmetry breaking in presence of two controllable asymmetries. We remarkably find that the characteristic features of spontaneous symmetry breaking, while dramatically destroyed by one asymmetry, can be entirely restored when a second asymmetry is introduced. In essence, asymmetries balance each other. Our study illustrates aspects of the universal unfolding of the pitchfork bifurcation. It also has practical implications, in particular showing that symmetry-breaking-based sensors can potentially exhibit divergent sensitivity even in presence of imperfections. Our experimental implementation built around an optical fibre ring additionally constitutes the first observation of the polarization symmetry breaking of passive nonlinear resonators.