Experimental delayed-choice entanglement swapping

By Xiao-song Ma, S. Zotter, Johannes Kofler, Rupert Ursin, T. Jennewein, Č. Brukner, Anton Zeilinger. Nature Physics, 2012

250 citations recorded by the source corpus.

Motivated by the question of which kind of physical interactions and processes are needed for the production of quantum entanglement, Peres has put forward the radical idea of delayed-choice entanglement swapping. There, entanglement can be ‘produced a posteriori, after the entangled particles have been measured and may no longer exist’. Here, we report the realization of Peres’s gedanken experiment. Using four photons, we can actively delay the choice of measurement—implemented through a high-speed tunable bipartite-state analyser and a quantum random-number generator—on two of the photons into the time-like future of the registration of the other two photons. This effectively projects the two already registered photons onto one of two mutually exclusive quantum states in which the photons are either entangled (quantum correlations) or separable (classical correlations). This can also be viewed as ‘quantum steering into the past’. In 2000, Asher Peres put forward the paradoxical idea that entanglement could be produced after the entangled particles have been measured, even if they no longer exist. Researchers now experimentally demonstrate this idea using four photons.

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/cc4db80f7f81e09bb8dddc7b5f99d1b2b1d8e728

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Citations in the corpus

Delayed-choice gedanken experiments and their realizations (2014, background): “A refined and conclusive realization of Peres’ gedanken experiment was reported (Ma et al., 2012).”
Consciousness In The Universe (2011, background): “Numerous other experiments have also provided strong indications of temporal anomalies in perception and willed choice [148–150].”
Quantum teleportation across a metropolitan fibre network (2016, background): “We point out that the 795 nm photons are measured prior to the BSM, thus realizing a scenario where teleportation is achieved a posteriori [17, 18].”
Quantum random number generators (2016, methodology): “…et al., 1993) after Peres’s proposal (Peres, 2000) in which whether two photons are entangled or not is decided after they have been measured (Ma et al., 2012) and in quantum erasure experiments that erase path information (Ma et al., 2013a), in both cases using the QRNG of (Jennewein et…”
Consciousness in the universe: a review of the 'Orch OR' theory. (2014, background): “Whenever we are asking for the manifestation of large-scale quantum effects in a warm system, we are not expecting that all the degrees of freedom should be simultaneously involved with these effects and therefore uniformly thermalized.”