In recent years, the physics community has been captivated by the newly described phase of matter known as a ‘time crystal’, with broken time-translation symmetry, analogous to conventional crystals in which space-translation symmetry is broken. In nature, these symmetry-breaking crystalline states with long-range order are achieved spontaneously through a phase transition (for example, from water to ice). Isotropic homogeneous matter is invariant under space-translation symmetry while in crystals with periodic atomic lattices that symmetry is broken. The phenomenon is of interest to the study of dynamic classical many-body states in the strongly correlated regime and applications in all-optical modulation, frequency conversion and timing. Here we report that a classical metamaterial nanostructure, a two-dimensional array of plasmonic metamolecules supported on flexible nanowires, can be driven to a state possessing all of the key features of a continuous time crystal: continuous coherent illumination by light resonant with the metamolecules’ plasmonic mode triggers a spontaneous phase transition to a superradiant-like state of transmissivity oscillations, resulting from many-body interactions among the metamolecules, characterized by long-range order in space and time. Quantum time crystals with discretely broken time-translation symmetry have been demonstrated in trapped ions, atoms and spins whereas continuously broken time-translation symmetry has been observed in an atomic condensate inside an optical cavity. Claverie, P.: Analysis of multiexponential functions without a hypothesis as to the number of components.Time crystals are an eagerly sought phase of matter with broken time-translation symmetry. J.: Search for a short-range, isospin-coupling component of the fifth force with use of a beam balance. Thieberger, P.: Search for a substance-dependent force with a new differential accelerometer. R.: Modulated source Eötvös experiment at Little Goose Lock. Szumilo, A.: Search for an intermediate-range composition-dependent force. Watanabe, R.: Limits on composition-dependent interactions using a laboratory source: Is there a “fifth force” coupled to isospin?. Watanabe, R.: Search for the intermediate-range interaction. Watanabe, R.: New constraints on composition-dependent interactions weaker than gravity. Rösch, N.: Search for non-newtonian gravitation - a gravimetric experiment in a hydroelectric lake (preprint, 1989)Īdelberger, E. D.: A lake experiment for measurement of the gravitational constant on a scale of tens of meters (preprint 1988) D.: A determination of the gravitational constant at an effective mass separation of 22 m. Mazilu, P.: Actio-reactio equations with finite wave speed derived from the principle of inertia.

Mazilu, P.: Über den Zusammenhang zwischen den jtingsten geophysikalischen Messungen der Gravitationskonstante und den Experimenten von Brush und Eötvös. W.: Tower gravity experiments evidence for non-Newtonian gravity. T.: Borehole measurements of the Newtonian gravitational constant. J.: Gravity in mines - An investigation of Newton's law. J.: A new mine determination of the Newtonian gravitational constant. Morris, D.: Constraint on the planetary scale value of the Newtonian gravitational constant from the gravity profile within a mine.

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