Posts by Collection



Effective intermittency and cross correlations in the standard map

Published in Physical Review E, 2015

We define auto- and cross-correlation functions capable of capturing dynamical characteristics induced by local phase-space structures in a general dynamical system. These correlation functions are calculated in the standard map for a range of values of the nonlinearity parameter k. Using a model of noninteracting particles, each evolving according to the same standard map dynamics and located initially at specific phase-space regions, we show that for 0.6<k≤1.2 long-range cross correlations emerge. They occur as an ensemble property of particle trajectories by an appropriate choice of the phase-space cells used in the statistical averaging. In this region of k values the single-particle phase space is either dominated by local chaos (k≤kc with kc≈0.97) or it is characterized by the transition from local to global chaos (kc<k≤1.2). Introducing suitable symbolic dynamics we demonstrate that the emergence of long-range cross correlations can be attributed to the existence of an effective intermittent dynamics in specific regions of the phase space. Our findings support the recently established relation of intermittent dynamics and cross correlations [F. K. Diakonos, A. K. Karlis, and P. Schmelcher, Europhys. Lett. 105, 26004 (2014)] in simple one-dimensional intermittent maps, suggesting its validity also for two-dimensional Hamiltonian maps.

Recommended citation: G. Datseris, F. K. Diakonos, and P. Schmelcher, Phys. Rev. E 92, 012914 (2015)


Jumping into Julia


Half-day workshop that introduced the Julia programming language to scientists already familiar with programming.

Husimi Functions in graphene: Measuring Klein Tunneling


Using the Husimi function in scattering wavefunctions obtained in tight-binding simulations of nanodevices. Extending the concept of the Husimi function for electrons moving in magnetic fields. Applying these tools in graphene, specifically to study Klein tunneling from a different perspective.

Kac’s Lemma and solid-state nanodevices?


Talk about the billiards aspect of the first half of my Ph.D., mainly revolving about how we used Kac’s lemma to connect and prove the fundamental phase-space properties of billiards with the resistance of solid state nanodevices.