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Time in a Hot Big Bang - No GUT

  1. Dec 29, 2015 #1
    I was thinking about the concept of Unification at extreme energies, and how the symmetry breaking / condensation as a result of universal expansion resolves the necessary fields for our universe.
    As such, it stands to reason to consider a Hot Big Bang as candidate for the arena to allow for the scenario of such unification.
    My question is that at some point in such a Hot Unified universe, 'before' the condensation/symmetry breaking to result in a Higgs field, there were no 'massive' particles. Weak and Electroweak fields require much lower energies to condense, so for whatever form the energy of the universe consisted of, there was no temporal metric.
    There was no distinction between past, present or future and nothing by which 'time' could be discerned excluding the expansion of the universe itself - which would mean the universe would continue in this state 'forever' (though forever would not exist as a concept).
    Therefore, it seemed to indicate that there could be no complete unification, some quantity must 'always' have existed distinct from others so as to provide a 'frame of reference' from which the passage of time could be measured, this difference could be attributed to the quantum fluctuations?

    Does this make sense? Is it accurate? Am I missing something? Could the expansion of the universe instead actually form a 'clock'?
     
  2. jcsd
  3. Dec 29, 2015 #2

    Orodruin

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    It is unclear to me why you draw this conclusion. The metric is a property of the space-time, not of the field. Massless fields, such as the photon field, still build upon a pseudo-Riemannian space-time. The fact that it is massless does not change that.
     
  4. Jan 2, 2016 #3
    Progress of time (time arrow) is related to growth of entropy.
    Growth of entropy was going on even in very hot Universe with strong and electroweak forces presumably unified.
    Hence there was time arrow even there.
     
  5. Jan 15, 2016 #4
    To me, this is insufficient.

    Once I was asked by a physics graduate, "How do you define time?", I knew they expected me to quote the usual tendency for entropy to increase as providing a directional 'arrow' for time, but refused. I will not explain my actual answer here because that's not relevant to this thread. However, that there is nothing except a non-zero probability to suggest that entropy will increase. There is also a non-zero probability that entropy will decrease and a non-zero probability that entropy will remain static.
    There is nothing which "compels" any such entropic increase.

    Secondly, what is entropy, but a measure of the degrees of freedom within a system - In a universe comprised only of photon-like massless entities* what actual freedoms could there be?

    Thirdly, from what frame of reference is this supposed measure of entropy from?



    Right, yes I can appreciate that distinction, but how can the 'photons'* or the field as a whole be affected by this 'proper time' in order for further condensation? In essence, how can they 'feel' the effect of time passing?
    Whilst you are right, that time of course is inherently within spacetime, sine all entities experience time locally and relatively, how can there be any means to discern any change of time when there's nothing that can 'feel it' ?

    I apologise for the very poor attempt at description, I hope you can understand what I'm trying to say, even if it's not correct!



    *I use photon because I can only presume such primordial entities would have similar properties and lack any suitable alternative.
     
  6. Jan 15, 2016 #5

    Orodruin

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    This is a more philosophical question than a physical one.
    The physics will give you as good of a description of how things behave, but you will always have the option of asking why. This is (at least at the moment) purely philosophical and therefore not something we deal with here (we discuss physics, not philosophy).
     
  7. Jan 15, 2016 #6
    Thanks!

    I didn't mean the queston to be non-physical.
    Obviously I did not mean the words "feel" to be anything other than some form of interaction etc. Of course there is no 'intent', emtion', nor 'purpose' in such matters -

    Given your answer, I think maybe I was trying to ask what process connects the time of spacetime to massless particles that does not require some component which changes over time, i.e. the spontaneous, repetitive parity breaking of the weak hypercharge?

    If this is a question that, for now, there is no available answer, then I can let it rest and thank you for your insight. Otherwise, is it truly such a philospophical point?
     
  8. Jan 15, 2016 #7

    Orodruin

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    No there is no process. There is a description of how the phase of the electromagnetic field behaves in relation to space-time.
     
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