Leuch A Papariello L Zilberberg O Degen CL Chitra R Eichler A 2016 Much of the physical world around us can be described in terms of harmonic oscillators in thermodynamic equilibrium. At the same time, the far-from-equilibrium behavior of oscillators is important in many aspects of modern physics. Here, we investigate a resonating system subject to a fundamental interplay between intrinsic nonlinearities and a combination of several driving forces. We have constructed a controllable and robust realization of such a system using a macroscopic doubly clamped string. We experimentally observe a hitherto unseen double hysteresis in both the amplitude and the phase of the resonator's response function and present a theoretical model that is in excellent agreement with the experiment. Our work unveils that the double hysteresis is a manifestation of an out-of-equilibrium symmetry breaking between parametric phase states. Such a fundamental phenomenon, in the most ubiquitous building block of nature, paves the way for the investigation of new dynamical phases of matter in parametrically driven many-body systems and motivates applications ranging from ultrasensitive force detection to low-energy computing memory units. application/pdf https://sonar.ch/global/documents/277296 eng info:eu-repo/semantics/altIdentifier/doi/10.1103/PhysRevLett.117.214101 info:eu-repo/semantics/altIdentifier/pmid/27911547 info:eu-repo/semantics/openAccess Physical review letters. - 2016 Parametric Symmetry Breaking in a Nonlinear Resonator. http://purl.org/coar/resource_type/c_6501