Mainz 2017 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 34: Quantum Effects: Entanglement and Decoherence
Q 34.1: Gruppenbericht
Mittwoch, 8. März 2017, 14:30–15:00, P 4
Tunable entanglement resource in elastic electron-exchange collisions out of chaotic spin systems — •Bernd Lohmann1, Karl Blum1, and Burkhard Langer2 — 1Institut für Theoretische Physik, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Strasse 9, 48149 Münster, Germany — 2Physikalische Chemie, Freie Universität Berlin, Taku-Strasse 3, 14195 Berlin, Germany
Elastic collisions between initially unpolarized electrons and hydrogenlike atoms are discussed aiming to analyze the entanglement properties of the correlated final spin system. Explicit spin-dependent interactions are neglected and electron exchange only is taken into account. It is shown that the final spin system is completely characterized by a single spin correlation parameter depending on scattering angle and energy. Its numerical value identifies the final spins of the collision partners to be either in the separable, entangled, or Bell correlated regions.
The symmetry of the scattering process allows for the construction of explicit examples applying methods of classical communication and local operations for illustrating the concepts of nonlocality versus separability.
It is shown that strong correlations can be produced violating Bell's inequalities significantly. Furthermore, the degree of entanglement can be continuously varied simply by changing either the scattering angle and/or energy. This allows for the generation of tunable spin pairs with any desired degree of entanglement. We suggest to use such nonlocally entangled spin pairs as a resource for further experiments, for example in quantum information processes.