Stuttgart 2012 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
A: Fachverband Atomphysik
A 26: Poster: Atomic systems in external fields
A 26.4: Poster
Mittwoch, 14. März 2012, 16:30–19:00, Poster.V
Fingerprints of exceptional points in the survival probability of resonances in atomic spectra — •Holger Cartarius1,2, Günter Wunner1, Jörg Main1, and Nimrod Moiseyev3 — 11. Institut für Theoretische Physik, Universität Stuttgart — 2Chemical Physics Department, Weizmann Institute of Science, Rehovot, Israel — 3Department of Physics and Minerva Center for Nonlinear Physics of Complex Systems, Technion, Haifa, Israel
Exceptional points, i.e. branch point singularities in non-Hermitian physical systems, where two complex eigenvalues degenerate and the corresponding eigenstates coalesce, have shown to exhibit prominent effects not observable in their absence. They appear in quantum resonance spectra and have been found for decaying unbound states of the hydrogen atom in crossed electric and magnetic fields [1].
For the decay of two resonances exactly at the exceptional point parameters a unique time signature is expected. We show that indeed the survival probability S(t)=|⟨ψ(0)|ψ(t)⟩|2 decays exactly as |1−a t|2 e−ΓEPt/ℏ where ΓEP is associated with the decay rate at the exceptional point and a is a complex constant depending solely on the initial wave packet that populates exclusively the two almost degenerate states of the non-Hermitian Hamiltonian [2]. This may open the possibility for a first experimental detection of exceptional points in a quantum system.
[1] H. Cartarius, J. Main, G. Wunner, Phys. Rev. Lett. 99, 173003 (2007)
[2] H. Cartarius, N. Moiseyev, Phys. Rev. A 84, 013419 (2011)