Berlin 2014 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 47: Attosecond physics
A 47.6: Vortrag
Donnerstag, 20. März 2014, 17:45–18:00, BEBEL E42
Non-Equilibrium Dynamics Manifested by Fluctuations in a Quantum Many-Body System: Giant Dipole Resonance of Atomic Xenon — •Yi-Jen Chen1,2, Stefan Pabst1, and Robin Santra1,2 — 1Center for Free-Electron Laser Science, DESY, Hamburg, Germany — 2Department of Physics, University of Hamburg, Hamburg, Germany
For a quantum many-body system driven out of equilibrium, the dynamics of the system is typically characterized by the expectation value of a suitable observable. The purpose of this work is to evaluate the information inaccessible by the dynamics of the average yet contained in the dynamics of the uncertainty. To this end, many-electron atomic xenon is chosen as the model system. Using ultrashort XUV pulses, we excite the Xe giant dipole resonance, a well-known example among atomic systems where the collective excitation of the electrons in the 4d shell plays a prominent role. The system is numerically propagated with the ab-initio time-dependent configuration-interaction singles method. We calculate the expectation value of a one-body operator, here the total dipole momentum, and the corresponding uncertainty. We point out the new information extracted from the dynamics of the uncertainty, with special attention to electronic correlation and the coherence between different configurations. By turning on and off the interchannel coupling in the simulation, the sensitivity of the uncertainty as a probe for many-body effects is also discussed.