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.
. . .