Revealing geometric phases in modular and weak values with a quantum eraser

Research output: Contribution to journalArticle


We present a procedure to completely determine the complex modular values of arbitrary observables of pre- and postselected ensembles, which works experimentally for all measurement strengths and all postselected states. This procedure allows us to discuss the physics of modular and weak values in interferometric experiments involving a qubit meter. We determine both the modulus and the argument of the modular value for any measurement strength in a single step, by simultaneously controlling the visibility and the phase in a quantum eraser interference experiment. Modular and weak values are closely related. Using entangled qubits for the probed and meter systems, we show that the phase of the modular and weak values has a topological origin. This phase is completely defined by the intrinsic physical properties of the probed system and its time evolution. The physical significance of this phase can thus be used to evaluate the quantumness of weak values.

Original languageEnglish
Article number042124
JournalPhysical Review A - Atomic, Molecular, and Optical Physics
Issue number4
Publication statusPublished - 28 Apr 2016

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    A geometric approach to modular and weak values

    Author: Cormann, M., 7 Jul 2017

    Supervisor: Caudano, Y. (Supervisor), Hespel, B. (Co-Supervisor), Lambin, P. (President), Martin, J. (External person) (Jury) & Matzkin, A. (External person) (Jury)

    Student thesis: Doc typesDoctor of Sciences


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