SAMOP 2021 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
A: Fachverband Atomphysik
A 16: Ultra-cold atoms, ions, and BEC (joint session A/Q)
A 16.24: Poster
Mittwoch, 22. September 2021, 16:30–18:30, P
Collisions of solitary waves in condensates beyond mean-field theory — •Aparna Sreedharan1, S Choudhury1, R Mukherjee1,2, A Streltsov3,4, and S Wüster1 — 1Department of Physics, IISER Bhopal, Madhya Pradesh 462066, India — 2Department of Physics, Imperial College, SW7 2AZ, London, UK — 3Theoretische Chemie, Physikalisch-Chemisches Institut, Universität Heidelberg, Germany — 4SAP Deep Learning Center of Excellence and Machine Learning Research SAP SE, Germany
A soliton is a self-reinforcing wave packet that maintains its shape despite dispersion, and appears in a large number of natural nonlinear systems including BEC. Solitons with a density maximum are referred to as bright solitons and those in BEC are composed of hundreds or thousands of identical atoms held together by their weak contact interactions. They behave very much like a compound object, with behaviour dictated by the nonlinear wave equation describing the mean field of their many body wave function. Soliton interactions in BEC are strongly affected by condensate fragmentation dynamics which we study using the TWA and MCTDHB. We also show that separate solitary waves decohere due to phase diffusion that depends on their effective ambient temperature, after which their initial mean-field relative phases are no longer well defined or relevant for collisions. In this situation, collisions are predominantly repulsive and can no longer be described within mean-field theory. Using different quantum many body techniques, we present a unified view on soliton fragmentation, phase diffusion and entanglement in their collision dynamics.