Saturday, December 12, 2015

I'm quantum walking backwards for Christmas*

I didn't care all that much for Adam Gopnik's recent New Yorker piece talking about science, and in particular, "spooky action at a distance", but I did like the end of this paragraph:
What started out as a reductio ad absurdum became proof that the cosmos is in certain ways absurd. What began as a bug became a feature and is now a fact. Musser takes us into the lab of the Colgate professor Enrique Galvez, who has constructed a simple apparatus that allows him to entangle photons and then show that “the photons are behaving like a pair of magic coins. . . .They are not in contact, and no known force links them, yet they act as one.” With near-quantum serendipity, the publication of Musser’s book has coincided with news of another breakthrough experiment, in which scientists at Delft University measured two hundred and forty-five pairs of entangled electrons and confirmed the phenomenon with greater rigor than before. The certainty that spooky action at a distance takes place, Musser says, challenges the very notion of “locality,” our intuitive sense that some stuff happens only here, and some stuff over there. What’s happening isn’t really spooky action at a distance; it’s spooky distance, revealed through an action.
A clever way to put it!

Speaking of spooky action, I also noticed this week on arXiv another paper (he has many) by Australian philosopher Huw Price (and Ken Wharton) entitled "A Live Alternative to Quantum Spooks"  about how retrocausality could an explanation. even though this possibility is pretty routinely overlooked.  Here's the crucial page:

If I understand him correctly, Price argues that this type of retrocausality preserves free will - it's just that the consequences of it can work both forwards and backwards.  (!)

He also says that this couldn't be used for potentially paradox causing signalling to the past: 
It couldn’t be used to signal for much the same reason that entanglement itself can't be used to signal
Well, he's convinced me of the possibility.  Now if only the physicists will get on board...

*  for the young reader:  a topical reference to a song from the Goon Show.


John said...

Thanks Steve,

I have read a previous text by Huw Price, generally recognised as one of the better philosophers dealing with QM. I have sought the opinions of two physicists who have helped me in the past. It will be interesting to see what they have to say because generally I prefer not to have opinions about QM.

This statement is ridiculous

What started out as a reductio ad absurdum became proof that the cosmos is in certain ways absurd.

What does it mean to be absurd in this context? I have never had a problem with spooky action at a distance because that is just a rational idea about ontology and come and go in all too frequent intervals.

George Musser said...

You refer to my book; as it happens, I do discuss retrocausality there. I think it's a plausible alternative to "spooky action", but has some of the same implications - namely, to question conventional ideas of spacetime. Also see my longer discussion at