In the discussion following the first Callender article, there was much criticism voiced concerning people lifting "uncertainty" from physics and trying to misapply it out of context. In view of which, it was both amusing and provocative to encounter later the same day in http://terrytao.wordpress.com/2013/07/26/computing-convolutions-of-measures << It is a challenge to make this intuition perfectly rigorous, as one has to somehow deal with the obstruction presented by the Heisenberg uncertainty principle, but it can be made rigorous in various asymptotic regimes, for instance using the machinery of wave front sets (which describes the high frequency limit of the phase space distribution). >> On 7/26/13, Dan Asimov <dasimov@earthlink.net> wrote:
I seem to have a mental block against learning even basic QM.
But I like Callender's mention that, taking the long view, the observer is not a privileged entity, but just another part of the universe that -- like every part of the universe -- interacts with every part of the universe.
--Dan
On 2013-07-26, at 10:08 AM, Mike Stay wrote:
"Measurement" is simply entangling the quantum state under observation with a macroscopic pointer state like a brain. When the pointer state is small enough that it can be kept coherent, one can disentangle the two systems after measurement and have the pointer state "unobserve" the other quantum state.
See the quantum eraser experiment---which you can do using a laser pointer, see http://www.sciam.com/slideshow.cfm?id=a-do-it-yourself-quantum-eraser ---and the delayed choice quantum eraser experiment. http://en.wikipedia.org/wiki/Delayed_choice_quantum_eraser
On Fri, Jul 26, 2013 at 9:07 AM, Michael Kleber <michael.kleber@gmail.com> wrote:
Callender, who wrote the NYT piece, already alluded to the "real" resolution of the "who counts as an observer" pseudo-paradox: What happens when you observe a system is that you are now *part of* the system. To someone outside, who has not yet observed, you yourself are in a state of quantum superposition based on what observation you made.
--Michael
On Fri, Jul 26, 2013 at 10:37 AM, David Makin <makinmagic@tiscali.co.uk>wrote:
In this context doesn't "observer" really mean "anything that would allow observation if someone looked" rather than someone actually looking....though without actually looking how you'd tell if there was still an effect I have no idea.
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