Rohrbach Science

Talks & Publications

A priori which-way information in quantum interference with unstable particles

In the summer of 2010, I had the opportunity to work with Dr. Dennis Krause at Wabash College on a project he was considering attempting a theoretical treatment of interference of quantum unstable particles (QuUP). This publication eventually came out of this project.


If an unstable particle used in a two-path interference experiment decays before reaching a detector, which-way information becomes available that reduces the detected interference fringe visibility V. Here we argue that even when an unstable particle does not decay while in the interferometer, a priori which-way information is still available in the form of path predictability 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, P is related to V through the duality relation P^2+V^2=1.


D.E. Krause, E. Fischbach, and Z.J. Rohrbach. “A priori which-way information in quantum interference with unstable particles.” Phys Lett A 378 (34), 2490 (2014)