We demonstrate that nonconvex Lagrangians, as contemplated in the theory of time crystals, can arise in the effective description of conventional, physically realizable systems. Such embeddings resolve dynamical singularities which arise in the reduced description. Microstructure featuring intervals of fixed velocity interrupted by quick resets-"Sisyphus dynamics"-is a generic consequence. In quantum mechanics, this microstructure can be blurred, leaving entirely regular behavior.
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http://dx.doi.org/10.1073/pnas.1908758116 | DOI Listing |
Sci Rep
March 2022
Departament de Fisica, Universitat Politecnica de Catalunya, Rambla Sant Nebridi 22, 08222, Terrassa, Barcelona, Spain.
Time crystal oscillations in interacting, periodically driven many-particle systems are highly regular oscillations that persist for long periods of time, are robust to perturbations, and whose frequency differs from the frequency of the driving signal. Making use of underlying similarities of spatially-extended systems and time-delayed systems (TDSs), we present an experimental demonstration of time-crystal-like behavior in a stochastic, weakly modulated TDS. We consider a semiconductor laser near threshold with delayed feedback, whose output intensity shows abrupt spikes at irregular times.
View Article and Find Full Text PDFPhys Rev Lett
November 2019
Abdus Salam ICTP, Strada Costiera 11, I-34151 Trieste, Italy.
We study synchronization between periodically driven, interacting classical spins undergoing a Hamiltonian dynamics. In the thermodynamic limit there is a transition between a regime where all the spins oscillate synchronously for an infinite time with a period twice the driving period (synchronized regime) and a regime where the oscillations die after a finite transient (chaotic regime). We emphasize the peculiarity of our result, having been synchronization observed so far only in driven-dissipative systems.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
September 2019
Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, MA 02139;
We demonstrate that nonconvex Lagrangians, as contemplated in the theory of time crystals, can arise in the effective description of conventional, physically realizable systems. Such embeddings resolve dynamical singularities which arise in the reduced description. Microstructure featuring intervals of fixed velocity interrupted by quick resets-"Sisyphus dynamics"-is a generic consequence.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!