Rostock 2019 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 25: Poster: Quantum Optics and Photonics I
Q 25.1: Poster
Tuesday, March 12, 2019, 16:30–18:30, S Atrium Informatik
Unequal-time correlations in Bose-Einstein condensates — •Linda Shen1, 2 and Martin Gärttner2 — 1Institut für Theoretische Physik, Philosophenweg 16, 69120 Heidelberg, Germany — 2Kirchhoff-Institut für Physik, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany
We develop measurement schemes for unequal-time correlation functions in a Bose-Einstein condensate (BEC). Both the spectral and statistical components of the two-point correlation function are investigated out of equilibrium. Thereby, the time-evolution of a BEC is computed numerically using classical-statistical simulation methods based on the Gross-Pitaevskii equation.
The spectral correlation function is approached by linear response methods, which are in principle applicable to both numerical computations as well as experimental measurements. The statistical correlation function can be computed directly in the classical-statistical approximation. Extracting the unequal-time statistical function experimentally, however, requires involved techniques in order to avoid quantum back action effects. We propose to use a non-invasive measurement protocol where the system is weakly coupled to an ancillary system.
In thermal equilibrium, the spectral and statistical components are related by the fluctuation-dissipation theorem. Measuring both will allow a better understanding of how the fluctuation-dissipation theorem builds up as the system approaches equilibrium.