Single-pair measurement of the Bell parameter
- URL: http://arxiv.org/abs/2303.04787v1
- Date: Wed, 8 Mar 2023 18:36:02 GMT
- Title: Single-pair measurement of the Bell parameter
- Authors: Salvatore Virz\`i, Enrico Rebufello, Francesco Atzori, Alessio Avella,
Fabrizio Piacentini, Rudi Lussana, Iris Cusini, Francesca Madonini, Federica
Villa, Marco Gramegna, Eliahu Cohen, Ivo Pietro Degiovanni, Marco Genovese
- Abstract summary: We present the first single-pair Bell inequality test, able to obtain a Bell parameter value for every entangled pair detected.
This is made possible by exploiting sequential weak measurements, allowing to measure non-commuting observables in sequence on the same state.
- Score: 0.0
- License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
- Abstract: Bell inequalities are one of the cornerstones of quantum foundations, and
fundamental tools for quantum technologies. Recently, the scientific community
worldwide has put a lot of effort towards them, which culminated with
loophole-free experiments. Nonetheless, none of the experimental tests so far
was able to extract information on the full inequality from each entangled
pair, since the wave function collapse forbids performing, on the same quantum
state, all the measurements needed for evaluating the entire Bell parameter. We
present here the first single-pair Bell inequality test, able to obtain a Bell
parameter value for every entangled pair detected. This is made possible by
exploiting sequential weak measurements, allowing to measure non-commuting
observables in sequence on the same state, on each entangled particle. Such an
approach not only grants unprecedented measurement capability, but also removes
the need to choose between different measurement bases, intrinsically
eliminating the freedom-of-choice loophole and stretching the concept of
counterfactual-definiteness (since it allows measuring in the otherwise
not-chosen bases). We also demonstrate how, after the Bell parameter
measurement, the pair under test still presents a noteworthy amount of
entanglement, providing evidence of the absence of (complete) wave function
collapse and allowing to exploit this quantum resource for further protocols.
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