We derive exact closed-form expressions for several sums leading to hyperbolic functions and discuss their applicability for studies of finite-size Ising spin chains. We show how they immediately lead to closed-form expressions for both fidelity susceptibility characterizing the quantum critical point and the coefficients of the counterdiabatic Hamiltonian enabling arbitrarily quick adiabatic d...

We study the microlocal structure of the resolvent of the semiclassical Schrödinger operator with short range potential at an energy which is a unique non-degenerate global maximum of the potential. We prove that it is a semiclassical Fourier integral operator quantizing the incoming and outgoing Lagrangian submanifolds associated to the fixed hyperbolic point. We then discuss two applications ...

A class of polynomial systems of odd degree with limit cycles, invariant parabolas and invariant straight lines, is examined. The limit cycles can be obtain as a bifurcation of a non hyperbolic focus at the origin as Hopf bifurcations. We will also obtain the necessary and sufficient conditions for the critical point at the interior of bounded region to be a center. 2010 Mathematics Subject Cla...

We have extended our method of grouping of Feynman diagrams (GFD theory) to study the transversal and longitudinal Greens functions G ⊥ (k) and G (k) in ϕ 4 model below the critical point (T < T c) in presence of an infinitesimal external field. Our method allows a qualitative analysis not cutting the perturbation series. We have shown that the critical behavior of the Greens functions is consi...

We consider parametrized families of diieomorphisms bifurcating through the creation of critical saddle-node cycles and we show that they exhibit H enon-like strange attractors for a set of parameter values which has positive Lebesgue density at the bifurcation value. This is the rst example of a bifurcation mechanism displaying such prevalence of H enon-like chaotic behaviour. Furthermore, for...

The end of a hyperbolic surface is studied in terms of the behavior at innnity of geodesics on the surface. For a class of surfaces called untwisted utes it is possible to give a fairly precise description of the ending geometry. From the point of view of a Fuchsian group representing such a surface this provides new information about the existence of Dirichlet and Garnett points. 0. Introducti...