Rostock 2019 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 28: Quantum Gases (Bosons) III
Q 28.7: Talk
Wednesday, March 13, 2019, 12:15–12:30, S HS 037 Informatik
Spin thermometry of individual neutral impurities coupled to a Bose-Einstein condensate — •Jens Nettersheim1, Felix Schmidt1, Daniel Mayer1, Daniel Adam1, Jennifer Koch1, Quentin Bouton1, Tobias Lausch1, and Artur Widera1, 2 — 1Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, Germany — 2Graduate School Materials Science in Mainz, Gottlieb-Daimler-Strasse 47, 67663 Kaiserslautern, Germany
The measurement of (local) thermodynamic properties of a quantum system is the key for a detailed understanding of thermalization and dynamic in nonequilibrium quantum systems. Temperature, i.e. the distribution of kinetic energy, was measured so far by investigating motional dynamics of the total system or impurities immersed.
Here, we present a novel way of local in-situ thermometry based on the spin dynamic of individual neutral Caesium (Cs) atoms with total spin F=3 in a Bose-Einstein condensate (BEC) with total spin F=1. Elastic collisions thermalize the impurity, reflecting temperature in the kinetic energy distribution of the impurities. By contrast, for spin-exchange processes, the competition between endo- and exoergic spin exchange, coupling the kinetic energy to the internal degree of motion, unambiguously maps the temperature onto the quasi-spin population of the impurity. The sensitivity of the thermometer can be adjusted via the external magnetic field changing the Zeeman energy splitting. Our work thus provides a novel way of performing in-situ thermometry by measuring internal state populations rather than atomic motion.