Using analytic properties of Blaschke factors we construct a family of analytic hyperbolic diffeomorphisms of the torus for which the spectral properties of the associated transfer operator acting on a suitable Hilbert space can be computed explicitly. As a result, we obtain explicit expressions for the decay of correlations of analytic observables without resorting to any kind of perturbation argument.
We prove that for Anosov maps of the $3$-torus if the Lyapunov exponents of absolutely continuous measures in every direction are equal to the geometric growth of the invariant foliations then $f$ is $C^1$ conjugated to his linear part.
The stability (or instability) of synchronization is important in a number of real world systems, including the power grid, the human brain and biological cells. For identical synchronization, the synchronizability of a network, which can be measured by the range of coupling strength that admits stable synchronization, can be optimized for a given number of nodes and links. Depending on the geometric degeneracy of the Laplacian eigenvectors, optimal networks can be classified into different sensitivity levels, which we define as a networks sensitivity index. We introduce an efficient and explicit way to construct optimal networks of arbitrary size over a wide range of sensitivity and link densities. Using coupled chaotic oscillators, we study synchronization dynamics on optimal networks, showing that cospectral optimal networks can have drastically different speed of synchronization. Such difference in dynamical stability is found to be closely related to the different structural sensitivity of these networks: generally, networks with high sensitivity index are slower to synchronize, and, surprisingly, may not synchronize at all, despite being theoretically stable under linear stability analysis.
We investigate the stability of a one-parameter family of periodic solutions of the four-vortex problem known as `leapfrogging orbits. These solutions, which consist of two pairs of identical yet oppositely-signed vortices, were known to W. Grobli (1877) and A. E. H. Love (1883), and can be parameterized by a dimensionless parameter $alpha$ related to the geometry of the initial configuration. Simulations by Acheson (2000) and numerical Floquet analysis by Toph{o}j and Aref (2012) both indicate, to many digits, that the bifurcation occurs when $1/alpha=phi^2$, where $phi$ is the golden ratio. This study aims to explain the origin of this remarkable value. Using a trick from the gravitational two-body problem, we change variables to render the Floquet problem in an explicit form that is more amenable to analysis. We then implement G. W. Hills method of harmonic balance to high order using computer algebra to construct a rapidly-converging sequence of asymptotic approximations to the bifurcation value, confirming the value found earlier.
Let $f : Xto X$ be a dominating meromorphic map on a compact Kahler manifold $X$ of dimension $k$. We extend the notion of topological entropy $h^l_{mathrm{top}}(f)$ for the action of $f$ on (local) analytic sets of dimension $0leq l leq k$. For an ergodic probability measure $ u$, we extend similarly the notion of measure-theoretic entropy $h_{ u}^l(f)$. Under mild hypothesis, we compute $h^l_{mathrm{top}}(f)$ in term of the dynamical degrees of $f$. In the particular case of endomorphisms of $mathbb{P}^2$ of degree $d$, we show that $h^1_{mathrm{top}}(f)= log d$ for a large class of maps but we give examples where $h^1_{mathrm{top}}(f) eq log d$.
In this paper we compare the method of Lagrangian descriptors with the classical method of Poincare maps for revealing the phase space structure of two degree-of-freedom Hamiltonian systems. The comparison is carried out by considering the dynamics of a two degree-of-freedom system having a valley ridge inflection point (VRI) potential energy surface. VRI potential energy surfaces have four critical points: a high energy saddle and a lower energy saddle separating two wells. In between the two saddle points is a valley ridge inflection point that is the point where the potential energy surface geometry changes from a valley to a ridge. The region between the two saddles forms a reaction channel and the dynamical issue of interest is how trajectories cross the high energy saddle, evolve towards the lower energy saddle, and select a particular well to enter. Lagrangian descriptors and Poincare maps are compared for their ability to determine the phase space structures that govern this dynamical process.