Heidelberg 2015 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 70: Ultracold Atoms, Ions and BEC V (with A)
Q 70.3: Vortrag
Freitag, 27. März 2015, 11:30–11:45, M/HS1
Loschmidt Echo in Fock Space — •Thomas Engl1, Julien Dujardin2, Peter Schlagheck2, Juan Diego Urbina1, and Klaus Richter1 — 1Institut für Theoretische Physik, Universität Regensburg, 93040 Regensburg, Germany — 2Département de Physique, Université de Liège, 4000 Liège, Belgium
The Loschmidt echo is a measure of stability of a quantum system with respect to an external perturbation. While for single particle systems the Loschmidt echo has been extensively studied , for the fundamental issue of quantum stability in interacting many-body systems only few, mainly numerical, results are available . However, the recent development of methods to describe many-body quantum systems in the semiclassical regime , allows to attack analytically this difficult problem.
Here, we consider bosonic atoms in an optical lattice well described by a Bose-Hubbard model, where the perturbation is given by a small difference of the on-site energies. In the disordered case, we compute both the amplitude and the modulus square of the Loschmidt echo using the new semiclassical methods. Our analytical results show excellent agreement when compared to numerical calculations.
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T. Engl, J. Dujardin, A. Argüelles, P. Schlagheck, K. Richter and J. D. Urbina, Phys. Rev. Lett. 112, 140403 (2014)