Universality of local weak interactions and its application for interferometric alignment.

Dziewior, Jan; Knips, Lukas; Farfurnik, Demitry; Senkalla, Katharina; Benshalom, Nimrod; Efroni, Jonathan; Meinecke, Jasmin; Bar-Ad, Shimshon et al. · Proc Natl Acad Sci U S A · 2019

basic_science · Level V

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Abstract

The modification of the effect of interactions of a particle as a function of its preselected and postselected states is analyzed theoretically and experimentally. The universality property of this modification in the case of local interactions of a spatially preselected and postselected particle has been found. It allowed us to define an operational approach for the characterization of the presence of a quantum particle in a particular place: the way it modifies the effect of local interactions. The experiment demonstrating this universality property provides an efficient interferometric alignment method, in which the position of the beam on a single detector throughout one phase scan yields all misalignment parameters.