Associated paper: http://arxiv.org/ftp/arxiv/papers/1203/1203.4834.pdf
Full writeup http://phys.org/news/2012-04-quantum-physics-mimics-spooky-action.html Cheers: Axil On Sun, May 6, 2012 at 1:32 PM, Terry Blanton <[email protected]> wrote: > http://www.nature.com/nphys/journal/vaop/ncurrent/full/nphys2294.html > > Experimental delayed-choice entanglement swapping > > Xiao-song Ma, Stefan Zotter, Johannes Kofler, Rupert Ursin, > Thomas > Jennewein, Časlav Brukner & Anton Zeilinger > > Abstract > > 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’. > > <more requires subscription> > > Now that *is* creepy. > > T > >
