Scaling relations and critical exponents for two dimensional two parameter maps

In this paper we calculate the critical scaling exponents describing the variation of both the positive Lyapunov exponent, λ + , and the mean residence time, $\langle$ τ $\rangle$ , near the second order phase transition critical point for dynamical systems experiencing crisis-induced intermittency. We study in detail 2-dimensional 2-parameter nonlinear quadratic mappings of the form: X n+1 =f 1 (X n , Y n ; A, B) and Y n+1 =f 2 (X n , Y n ; A, B) which contain in their parameter space (A, B) a region where there is crisis-induced intermittent behaviour. Specifically, the Henon, the Mira 1, and Mira 2 maps are investigated in the vicinity of the crises. We show that near a critical point the following scaling relations hold: $\langle$ τ $\rangle$ ~ |A – A c | -γ , (λ + – λ c + ) ~ |A – A c | βA and (λ + – λ c + ) ~ |B – B c | βB . The subscript c on a quantity denotes its value at the critical point. All these maps exhibit a chaos to chaos second order phase transition across the critical point. We find these scaling exponents satisfy the scaling relation γ=β B ( $\frac{1}{\beta_{A}}$ – 1), which is analogous to Widom’s scaling law. We find strong agreement between the scaling relationship and numerical results. Copyright EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg 2010

Interference of a Bose-Einstein condensate in a hard-wall trap: from nonlinear Talbot effect to formation of vorticity

We theoretically study the coherent expansion of a Bose-Einstein condensate in the presence of a confining impenetrable hard-wall potential. The nonlinear dynamics of the macroscopically coherent matter field results in rich and complex spatio-temporal self-interference patterns demonstrating a nonlinear Talbot effect, and the formation of vorticity and solitonlike structures