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Endervhar
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If QM requires a constant universal time, does this rule out closed time-like curves?
I was re-reading an article from New Scientist 10 June 2006; Marcus Chown's "Do the Cosmic Twist" and I recalled that I had been puzzled by the following first time round:
"The trouble is, quantum theory requires time to be "universal" - there should never be closed loops of time isolated from the time in the rest of the universe".
Thanks, Ben. Is there any way I can make the article available on this forum without infringing copyright?
The various developments of quantum field theory in curved space-time have left the false impression that general relativity and quantum mechanics are compatible as long as one considers the length scales well above the Planck length [p. 2]
It turns out that certain predictions of classical general relativity such as closed time-like curves and event horizons are in conflict with a quantum mechanical description of space-time itself. In particular, a quantum mechanical description of any system requires a universal time. In practice, universal time is defined by means of synchronization of atomic clocks, but such synchronization is not possible in space-times with event horizons or closed time-like curves. [p. 2]
The various developments of quantum field theory in curved space-time have left the false impression that gen- eral relativity and quantum mechanics are compatible. Actually though certain predictions of classical general relativity such as closed time-like curves and event hori- zons are in conflict with a quantum mechanical descrip- tion of space-time itself. In particular, a quantum me- chanical description of any system requires a universal time. In practice, universal time is defined by means of synchronization of atomic clocks, but such synchroniza- tion is not possible in space-times with event horizons or closed time-like curves.
On the other hand, he doesn't believe in black holes!
There is no suggestion in the article that either Mazur or Chapline doubt the existence of black holes.