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arXiv · 2009.02829

Characterizing mixed state entanglement through single-photon interference

Mayukh Lahiri·Radek Lapkiewicz·Armin Hochrainer·Gabriela Barreto Lemos·Anton Zeilinger
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Abstract

Entanglement verification and measurement is essential for experimental tests of quantum mechanics and also for quantum communication and information science. Standard methods of verifying entanglement in a bipartite mixed state require detection of both particles and involve coincidence measurement. We present a method that enables us to verify and measure entanglement in a two-photon mixed state without detecting one of the photons, i.e., without performing any coincidence measurement or postselection. We consider two identical sources, each of which can generate the same two-photon mixed state but they never emit simultaneously. We show that one can produce a set of single-photon interference patterns, which contain information about entanglement in the two-photon mixed state. We prove that it is possible to retrieve the information about entanglement from the visibility of the interference patterns. Our method reveals a distinct avenue for verifying and measuring entanglement in mixed states.

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Mayukh Lahiri, Radek Lapkiewicz, Armin Hochrainer, Gabriela Barreto Lemos, Anton Zeilinger. 2020-09-06. Characterizing mixed state entanglement through single-photon interference. https://doi.org/10.1103/physreva.104.013704

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