Quantum optical tests of complementarity: Quantum eraser and the decoherence time of a local measurement process

Shi‐Biao Zheng

Ki-Young Cho, Jaewoo Noh

Guang-Liang Li

The principle of complementarity is one of the cornerstones of quantum theory. The aim of this study was to advance our understanding of complementarity by analyzing the role of delayed choice and quantum erasers in two-slit experiments, and by proposing experiments for verifying the analysis. The analysis is based on models consisting of measurable spaces and probability measures involved in the experiments. The main findings are as follows: (a) The complementarity principle manifests itself in such a way that wave and particle behaviors cannot be simultaneously observed almost surely with respect to any single, fixed measure. (b) Described by different measures, complementary properties can coexist in the same experimental setup. (c) Which-way information will not preclude or erase interference fringes. (d) Delayed choice and quantum erasers are irrelevant to testing complementarity. (e) It is possible for us to know through which slit each quantum object passed almost surely with respect to the measure corresponding to the slit while the interference pattern is intact. Based on the experiments analyzed, realizable experiments are proposed for verifying the above results.

Marian O. Scully, Berthold‐Georg Englert, HERBERT WALTHER

L. Davidovich

Yonatan Abranyos, Matthias Jakob, János A. Bergou

We propose a which path quantum eraser scheme based on a recent experiment by Eichmann et al. [Phys. Rev. Lett. 70, 2359 (1993)] involving two four-level atoms. We show that the quantum eraser can be used for the detection of the decoherence time of macroscopic or mesoscopic entangled superpositions of pointer states of a meter with one of the two atoms, by the visibility of the interference pattern.