Karl Franzens University Graz

Graz University of Technology 

The complex dynamics of Fermi Pasta Ulam Tsingou process revealed in optical fiber systems
Prof. Dr. Arnaud Mussot
Université de Lille
16:15 - 17:15 Tuesday 21 January 2025 TUG

The Fermi–Pasta–Ulam–Tsingou (FPUT) recurrence process is a universal phenomenon that describes the natural cycle through which a nonlinear system returns to its initial state after undergoing complex coupling dynamics. This phenomenon can be observed in optical fibers by leveraging its analogy to modulation instability—a universal process in physics. In optics, MI plays a foundational role in supercontinuum generation, rogue wave formation, and frequency comb generation for instance. Here, we report on the observation of various distinct characteristics of FPUT recurrences, within an advanced photonic system. We developed a near-loss less optical fiber setup capable of tracking the longitudinal evolution of the electric field’s (intensity and phase). This non invasive method allows us to capture and analyze the intricate dynamics of this nonlinear system, revealing phenomena such as symmetry breaking and the pathway to thermalization within the FPUT recurrence process.

References :
Mussot, A. et al. Fibre multi-wave mixing combs reveal the broken symmetry of Fermi–Pasta–Ulam recurrence. Nature Photonics 12, 303–308 (2018).

G. Vanderhaegen, et al. “Heterodyne optical time-domain reflectometer combined with active loss compensation: a practical tool for investigating Fermi Pasta Ulam recurrence process and breathers dynamics in optical fibers”, FRONTIERS IN PHYSICS doi: 10.3389/fphy.2021.637812 (2021)

Speaker bio: Arnaud Mussot received the Ph.D. in Physics from University of Besancon in 2004 in France. Until 2005 he had a post doc position at the French Atomic Agency (CEA) in Bordeaux. In 2005 he joined the University of Lille in France as a lecturer and he was appointed full professor in 2014. His main interests focus on ultrafast nonlinear effects in optical fibers, parametric effects, resonators, and optical frequency combs. He has co-authored 160 papers in peer-review journals, gave more than 60 Invited talks at international conferences and holds 8 patents. He is Optica fellow since 2023 and senior member of the institut universitaire de France.
ORCID ID : http://orcid.org/0000-0002-6428-9443
Google scholar : https://scholar.google.ca/citations?user=CPQ70xgAAAAJ&hl=en