I got email last week from the Institute of Physics pointing me to a pair of video interviews with Anton Zeilinger of the University of Vienna. Zeilinger has built an impressive career out of doing fundamental tests of quantum mechanics– he’s not only got the accent and the hair to be a brilliant physicist, he’s got a long list of amazing experimental papers to back it up.
They’ve gone the Locus route, and not included any of the questions he was responding to, which is always a little weird. Zeilinger provides enough context that everything makes sense, though, and he says some really interesting things about his background, and the current and future state of quantum physics.
He looks uncharacteristically un-ruffled there. His hair is usually wilder and his clothes are usually more disheveled. He’s a nice guy too. I’ve always wanted to work on something with him.
Zeilinger is perhaps most famous for his part describing the GHZ state which the below link says “is an entangled quantum state having extremely non-classical properties.” (The name also makes it hard to search in Google, why the hell don’t they make case-sensitive easier?)
http://www.quantiki.org/wiki/index.php/GHZ
Well, I’ll just put this topical query out gently: Leaving aside debate about how to interpret “collapse of the wave function” etc., I wonder: Given a case of a beam splitter, like MZ interferometer etc, why doesn’t the first beam splitter “collapse” the WF? I mean, what is special about “detectors” versus “half-silvered mirrors”? If we have black spots at the other end of the MZ, we figure the light finally “hit” as photons. But the wave didn’t just go one way versus the other at the BS (because we can get interference later.) And like I said, the distinction between the two sorts of interaction is not to be confused with what you think collapse ultimately is, and (given BS, “black patches,” is not directly about “observers” in the sentient sense.)
More ruminations and examples at my blog.