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Q: Fachverband Quantenoptik und Photonik

Q 22: Ultracold Matter (Bosons) II (joint session Q/A)

Q 22.7: Vortrag

Dienstag, 11. März 2025, 12:30–12:45, HS I PI

Understanding Phonon Pair Production as 1d Scattering Problem — •Elinor Kath, Marius Sparn, Nikolas Liebster, Jelte Duchene, Helmut Strobel, and Markus K. Oberthaler — Kirchhoff-Institut für Physik, Universität Heidelberg

Non-adiabatically changing the interatomic interaction strength of a Bose-Einstein Condensate produces pairs of phonons, which interfere with the background condensate and become visible as density fluctuations. The resulting density fluctuation power spectrum depends on the details of the temporal shape of the interaction strength and, because the phonons were produced coherently, will still oscillate when the interaction strength is held constant again. This process of quasi-particle production can be mapped onto a quantum-mechanical scattering problem in 1d, where the time dependence of the interaction strength sets the height and shape of the scattering potential. We demonstrate how to apply this mapping to intuitively understand the shape and time dependence of produced phonon spectra.

Keywords: Phonon Production; Cosmological Particle Production; 1d Schrödinger Equation; 2d Bose-Einstein Condensate; Quantum Field Simulator