# Physics Seminar - Dr Antonio Muñoz Mateo

Monday, 31 July 2017

Physics Department
Seminar

## Dr Antonio Muñoz Mateo

### "Bright Solitons Collisions in Harmonically Trapped Bose-Einstein Condensates"

Motivated by a very recent experiment at Rice University, "Formation of matter-wave soliton trains by modulational instability", Science 356.6336 (2017), we address the issue of the apparently repulsive interactions between adjacent bright solitons. The experimental procedure exploits a Feshbach resonance to change the interparticle interaction from repulsive to attractive, thus leading the initial, elongated density profile of the atomic cloud to an unstable configuration against density modulations. The subsequent decay produces predominantly well-separated matter-wave solitons, which has been attributed to the existence of repulsive interactions between them, and hence to the spontaneous generation of a $\pi$ relative phase. We show that this particular relative phase is a distinctive feature of the stationary states of the trap, whose dynamics differs substantially from the observed time evolution of soliton trains randomly generated from a modulational instability. Our analysis goes over seminal works from the realm of optical fibers aiming at the reduction of soliton interactions in 1D systems, and show that the slow relative velocity and the differential amplitudes of the solitons can play a decisive role for the interpretation of the experimental outcome.

###### Authors:Antonio Muñoz Mateo and Joachim Brand, Dodd-Walls Centre for Photonic and Quantum Technologies and Centre for Theoretical Chemistry and Physics, New Zealand Institute for Advanced Study, Massey University

WHEN: Monday 31 July 2017
WHERE: Room 314, Science 3 Building
TIME: 3.00 pm–4.00 pm

All interested are welcome to attend

Light refreshments to follow in Common Room