Localisation of energy in the FPUT- α system with variability and its chaotic behaviour. 

  • Thu 20 Jan 22

    15:00 - 16:00

  • Online


  • Event speaker


  • Event type

    Lectures, talks and seminars

  • Event organiser

    Mathematical Sciences, Department of

  • Contact details

    Jesus Martinez-Garcia

These Departmental Seminars are for everyone in Maths. We encourage anyone interested in the subject in general, or in the particular subject of the seminar, to come along. It's a great opportunity to meet people in the Maths Department and join in with our community.

Localisation of energy in the FPUT- α system with variability and its chaotic behaviour. 

Fermi, Pasta, Ulam, and Tsingou studied one-dimensional lattices to model the crystal evolution towards thermal equilibrium. They expected to observe the equipartition of energy as predicted by the Boltzmann-Gibbs (BG) statistics due to nonlinearities in their model.

However, they noticed that almost all energy was back to its initial state after some period of steady state. This phenomenon, well-known as the FPUT recurrences, led to numerous discoveries in mathematics and physics. A recent study by Nelson et al. shows that if variability is incorporated in the FPUT system, it will limit the observance of recurrences. They numerically show that this variability can prevent recurrences in this system.

In this talk, we will discuss two-modes approximations in the normal mode coordinate to explain the localisation of energy for large enough variabilities. Moreover, we also investigate the chaotic behaviour of the FPUT-α system for different numbers of particles as we increase the variabilities by computing the maximum Lyapunov exponent and the SALI of this system.


Zulkarnain, University of Essex.

How to attend

If not a member of the Dept. Mathematical Science at the University of Essex, you can register your interest in attending the seminar and request the Zoom’s meeting password by emailing Dr Jesus Martinez-Garcia (jesus.martinez-garcia@essex.ac.uk)