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  • PRL125-020405

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Detection of Quantum Interference without an Interference Pattern

Research output: Contribution to Journal/MagazineJournal articlepeer-review

Article number020405
<mark>Journal publication date</mark>10/07/2020
<mark>Journal</mark>Physical review letters
Issue number2
Number of pages6
Publication StatusPublished
<mark>Original language</mark>English


Quantum interference is typically detected through the dependence of the interference signal on certain parameters (path length, Aharonov-Bohm flux, etc.), which can be varied in a controlled manner. The destruction of interference by a which-path measurement is a paradigmatic manifestation of quantum effects. Here we report on a novel measurement protocol that realizes two objectives: (i) certifying that a measured signal is the result of interference avoiding the need to vary parameters of the underlying interferometer, and (ii) certifying that the interference signal at hand is of quantum nature. In particular, it yields a null outcome in the case of classical interference. Our protocol comprises measurements of cross-correlations between the readings of which-path weakly coupled detectors positioned at the respective interferometer's arms and the current in one of the interferometer's drains. We discuss its implementation with an experimentally available platform: an electronic Mach-Zehnder interferometer (MZI) coupled electrostatically to "detectors" (quantum point contacts).

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© 2020 American Physical Society