The majority of Quantum Gravitists agree that the unified theory will get rid of space and time. But what does this mean? Does it mean letting a classical spacetime emerge from a summation over quantum geometries, such as spin foam graphs? No, of course not. It means removing space from one’s conception of the cosmos. When we observe binary pulsars for example, we should not imagine this object occupying a concrete objective classical spacetime out there. Even a traditional dynamical spacetime is completely inadequate. Quantum physics has taught us that a good way to approach a physical problem is to consider what we measure. One must be much more careful about the constraints one puts upon different classes of observation. If we wish to ‘observe’ the universe, we must define what we mean by this so that we are able to write down the correct geometry for this experiment.

People speak of holography in terms of data on a boundary. Where is this boundary? With respect to what may I position it? The best I can do is try to imagine that it is within myself.


5 Responses so far »

  1. 1

    L. Riofrio said,

    Great posts. Dark energy doesn’t exist? DWAT. String theory makes no testable predictions? DWAT. No major advances in physics for 30 years? DWAT. Hee hee!

  2. 2

    Mahndisa S. Rigmaiden said,

    11 11 06

    Kea you are asking good questions. Boundaries have always bothered me a bit. I was looking you up on arxiv and found a wonderous link to a paper that was recalled. Did you ever rewrite it? The abstract looked so interesting that I couldn’t resist bugging you about it!

  3. 3

    Kea said,

    Hi gals

    No, I never really rewrote that paper. I was severely reprimanded for posting it, and told there was no way in hell I was going to work on my own ideas for my PhD. Anyway, it’s a bit redundant now, ’cause my new paper with Mike is way, way cooler.

    Sorry I had to put in word verification. I was starting to get spammed.

  4. 4

    L. Riofrio said,

    “…severely reprimanded for posting it and told there was no way in hell I was going to work on my own ideas for my PhD.”

    Some days we wonder what is wrong with the world. Maybe the biggest boundaries are in people’s minds.

  5. 5

    Kea said,

    By the way, Mahndisa, if you click on v2 you can get a copy. Cheers.

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