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February 23, 2018

CATEGORY: The Nature of Time Essay Contest (2008) [back]
TOPIC: The Production of Time by Adam Daniel Helfer [refresh]
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Adam Daniel Helfer wrote on Dec. 2, 2008 @ 14:43 GMT
Essay Abstract

I suggest that measurement in quantum theory should be regarded as a sense of time (of things *happening*), which is as important as the conventional relativistic notion of time. A key question -- of basic physical interest whether one accepts the arguments here or not -- is, What physical criteria determine when a measurement takes place? I suggest a way in which the answer to this may be bound up with the resolution of some pathologies associated with the stress-energy operator, and may at the same time determine the cosmic flow of time. The problem of reconciling the quantum sense of time (measurement) and the conventional relativistic one gives some indication that the the correct "quantization" of gravity is essentially different from that of other fields.

Author Bio

Adam Helfer works on general relativity and quantum field theory.

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Carl Brannen wrote on Dec. 2, 2008 @ 22:11 GMT
I like this idea. You might be interested in Julian Schwinger's version of QM devoted to measurements. Do a google search for "measurement algebra"+Schwinger and see what comes up.

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Venerando wrote on Dec. 2, 2008 @ 22:53 GMT
I think that it is a great job. I not only agree with the exposed ideas, but also think they are well exposed, even for a low level degree in physics knowledge as mine. I’ve enjoyed this phrase:

“Is it really plausible that the Universe was in a gross macroscopic superposition of states until consciousness developed?”


Good luck with your job and in the contest.

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Dimi Chakalov wrote on Dec. 3, 2008 @ 03:37 GMT
Dear Adam,

You claim (p. 2) that "the main unanswered question in quantum theory is, When does a measurement occur?", and stressed (Sec. 5) that "a natural approach to understanding time in quantum theory is via its classically conjugate variable, energy." All this reminded me of the invisible cat, Macavity, which shows up only when no one is looking at it, just like the negative energy density in QFT (arXiv:gr-qc/9709047v2). Perhaps Macavity is always unobservable or gauge-dependent, and can be "located" only with a Gedankenexperiment from Wikipedia here.

I like your essay very much. The more I read it, the more I learn from you. Thank you.

Best regards -- Dimi

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Dr. E (The Real McCoy) wrote on Dec. 3, 2008 @ 04:30 GMT
Hello Adam.

Nice paper! Love the focus on meausrement, for without meausrement, there is no time, nor physics!

You write, "A key question -- of basic physical interest whether one accepts the arguments here or not -- is, What physical criteria determine when a measurement takes place?"

Consider the irreversible collapse of the photon's wave funcation in an act of...

view entire post

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Adam Helfer wrote on Dec. 10, 2008 @ 04:03 GMT

Thanks for yor comments. I recall the Schwinger measurement algebrea as an attempt to formalize the ideas of probability and interference.

Venerando, Dimi and Dr. E.,

Thanks for your comments. Yes, Dimi, the ideas here are related to those I figuratively associated with Macavity.

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Dimi Chakalov wrote on Dec. 11, 2008 @ 20:14 GMT

Glad to learn that the ideas in your Essay are related to the "invisible" (gauge-dependent?) cat Macavity (arXiv:gr-qc/9709047v2).

Please check out the so-called Buridan donkey paradox. Perhaps Macavity facilitates all "negotiations" between the donkeys. As you conjectured in your Essay (p. 3), "perhaps time is not merely a parameter, but another sort of thing, in quantum theory."

To the best of my knowledge, you are the first person to propose a new sort of time-energy uncertainty relation (Sec. 5.3, p. 8). I hope you will be awarded 10xFirst Prize in this contest.

Best - Dimi

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Dimi Chakalov wrote on Dec. 12, 2008 @ 15:58 GMT
P.S. I tried to vote for your Essay, but somehow the system didn't like it, and you still don't have any votes. Perhaps it will be a good idea if you elaborate more on your time-energy uncertainty relation (Sec. 5.3) and its implication to GR (Sec. 5.4), and then submit your research manuscript to PRL.

If there is anything I can do, just whistle.


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