Dresden 2011 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 61: Quantum Information: Concepts and Methods 4

Q 61.1: Vortrag

Freitag, 18. März 2011, 10:30–10:45, SCH A118

Phase-dependent wave-particle duality and delayed choice of the which-way detector observable — •Uwe Schilling and Joachim von Zanthier — Institut für Optik, Information und Photonik and Erlangen Graduate School in Advanced Optical Technologies (SAOT), Universität Erlangen-Nürnberg, 91058 Erlangen, Germany

It is well-known that when probing wave-particle duality in a two-way interferometer with a which-way detector, the amount of which-way information (WWI) depends on the observable which one reads out from the which-way detector. One may for example extract all WWI principally available [1] or, contrariwise, realize a quantum eraser [2] which erases all WWI. We introduce a still different observable which allows to either fully reveal or partially erase the WWI, depending on the phase shift in the interferometer [3]. In particular, for particles arriving in the minima of an interference pattern with V<1, the new observable enables us to extract full WWI which seems to contradict the inequality D² + V² ≤ 1 introduced in Ref. [1]. We resolve this ostensible contradiction for the case that only the new observable is measured [3]. However, we also show that D² + V² ≤ 1 may be violated by adeptly choosing the observable which is to be measured after the particle has been detected [4].

[1] B.-G. Englert, Phys. Rev. Lett. 77, 2154 (1996)

[2] M. O. Scully and K. Drühl, Phys. Rev. A 25, 2208 (1982)

[3] U. Schilling and J. von Zanthier, to be published

[4] U. Schilling and J. von Zanthier, quant-ph/1006.2037 (2010)