On Tue, Oct 22, 2019 at 9:42 AM 'Brent Meeker' via Everything List < [email protected]> wrote:
> > > Here's a good paper analyzing the experiment and showing it's entirely > explained just by the non-local correlation which is exemplified in the > effect of the space-like measurement choice. > > https://arxiv.org/ftp/arxiv/papers/1905/1905.03137.pdf > > Brent > Brent, I don't know why you think that this paper by Ruth Kastner is a good analysis of the Ma et al. experiment. As is usual with Ruth Kastner, she has got it all completely wrong. Her main argument seems to be that since the entangled photon pair form a singlet state, which is rotationally invariant, measuring in a particular "orthogonal" basis cannot erase anything because all bases are equivalent. But that is not how it works. Sure, the entangled photon pair produced by the parametric down conversion process is just an EPR pair, and that state is rotationally invariant. But the signal photon of this pair is then sent through a polarizing beam splitter, which sends one polarization state one way and the other polarization state the other way. This is already a polarization 'measurement', so it affects the other partner of the EPR pair in the usual non-local way, familiar from tests of Bell inequalities. So the idler photons carry the polarisation information induced by the measurement at the original polarizing beam splitter. So the EPR pair has been measured and is no longer rotationally invariant (or basis independent). Kastener's analysis is thus totally irrelevant because she has not understood the experimental set up. This is quite typical of Ruth Kastner -- she invariable gets things completely wrong. Bruce -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/CAFxXSLSiwLFgTzJNV84R4cPbS%3DkFW_n42qnUT7-mAN6s_VBaPA%40mail.gmail.com.
