We introduce diffraction-based interaction-free measurements. In contrast with previous work where a set of discrete paths is engaged, good-quality interaction-free measurements can be realized with a continuous set of paths, as is typical of optical propagation. If a bomb is present in a given spatial region—so sensitive that a single photon will set it off—its presence can still be detected without exploding it. This is possible because, by not absorbing the photon, the bomb causes the single photon to diffract around it. The resulting diffraction pattern can then be statistically distinguished from the bomb-free case. We work out the case of single- versus double-slit in detail, where the double-slit arises because of a bomb excluding the middle region.
Rogers, S., Aharonov, Y., Elouard, C. et al. Diffraction-based interaction-free measurements. Quantum Stud.: Math. Found. 7, 145–153 (2020). https://doi.org/10.1007/s40509-019-00205-6
This is a pre-copy-editing, author-produced PDF of an article that underwent peer review and was later accepted for publication in Quantum Studies: Mathematics and Foundations, volume 7, in 2020. The final publication may differ and is available at Springer via https://doi.org/10.1007/s40509-019-00205-6.
A free-to-read copy of the final published article is available here.