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arXiv · 1407.6762

A Priori Which-Way Information in Quantum Interference with Unstable Particles

D. E. Krause·E. Fischbach·Z. J. Rohrbach
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Abstract

If an unstable particle used in a two-path interference experiment decays before reaching a detector, which-way information becomes available which reduces the detected interference fringe visibility ${\cal V}$. Here we argue that even when an unstable particle does {\em not} decay while in the interferometer, {\em a priori} which-way information is still available in the form of path predictability ${\cal P}$ which depends on the particle's decay rate $Γ$. We further demonstrate that in a matter-wave Mach-Zehnder interferometer using an excited atom with an appropriately tuned cavity, ${\cal P}$ is related to ${\cal V}$ through the duality relation ${\cal P}^{2} + {\cal V}^{2} = 1$.

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D. E. Krause, E. Fischbach, Z. J. Rohrbach. 2014-07-24. A Priori Which-Way Information in Quantum Interference with Unstable Particles. https://doi.org/10.1016/j.physleta.2014.06.036

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