Locality and nonlocality in the interaction-free measurement

Daniel Rohrlich, Yakir Aharonov, Tomer Landsberger

Research output: Contribution to journalConference articlepeer-review


We present a paradox involving a particle and a mirror. They exchange a nonlocal quantity, modular angular momentum Lz mod 2ħ, but there seems to be no local interaction between them that allows such an exchange. We demonstrate that the particle and mirror do interact locally via a weak local current Lz mod 2ħw. In this sense, we transform the “interaction-free measurement" of Elitzur and Vaidman, in which two local quantities (the positions of a photon and a bomb in the two arms of a Mach-Zehnder interferometer) interact nonlocally, into a thought experiment in which two nonlocal quantities (the weak modular angular momentum of the particle and of the mirror) interact locally.

Original languageEnglish
Article number02105
JournalEPJ Web of Conferences
StatePublished - 3 Aug 2018
Event6th International Conference on New Frontiers in Physics, ICNFP 2017 - Crete, Greece
Duration: 17 Aug 201729 Aug 2017


FundersFunder number
John Templeton Foundation43297
Israel Science Foundation1190/13


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