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CPT theorem and entropy

  1. Jul 26, 2004 #1
    Entropy does not allow things to happen in reverse in time.
    In CPT theorem would this mean that entropy represents a T violation
    of some sort?
     
    Last edited: Jul 26, 2004
  2. jcsd
  3. Jul 27, 2004 #2
    You are correct. But no one has a good explanation why.
     
  4. Jul 27, 2004 #3
    Increase of entropy is just one of the four time's arrows.

    1. Thermodynamics (entropy) - Heat flows from hot to cool.
    2. Electromagnetic - Radiation emanate outward from source.
    3. Cosmology - The universal expansion of space.
    4. Psychology - We remember the past not the future.
     
  5. Jul 27, 2004 #4

    Alkatran

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    I thought life took unordered stuff and turned it into order? Isn't that going against entropy? (The energy coming from the sun is not ordered, right?)
     
  6. Jul 27, 2004 #5
    Relatively speaking, at the local region of any open system, order is seemed to be realized but there is always some amount of energy loss in the form of heat to the environment.

    If we shuffle a brand new ordered deck of cards, we need to spend energy. The more we shuffle the more random is the deck of cards but the more energy is spended. The increase in randomness of the deck of cards is entropy. How much we have to shuffle to regain the original order of the deck of cards?
     
  7. Jul 27, 2004 #6
    Energy flows from hot to cold.This is a net flow that has one space direction
    and one time direction.CP and T are violated so CPT symmetry is restored.
    The fact that no process has been found which breals CPT symmetry might just be because no process can break the second law of thermodynamics.

    Space might be expanding i.e dark energy increasing, because
    dark energy has entropy that increases with time - that is to say:
    dark energy has energy microstates.If it does have microstates then it
    could absorb energy from other particles in the universe e.g microwave background photons.
     
    Last edited: Jul 27, 2004
  8. Jul 28, 2004 #7
    Are you referring to the ultra-high frequency polarized radiation? Short wavelengths comparable to Planck length?
     
  9. Jul 28, 2004 #8
    I'm just suggesting that dark energy if it has microstates could be absorbing nergy from photons and other particles in the universe.It is my belief that dark energy + vacuum particle energy + energy of antimatter = constant if dark energy is made from vacuum energy and/or antimatter enrgy.
     
  10. Jul 28, 2004 #9
    Is microstate the same as a wave function, [itex] \psi [/itex]? If it is, this implies that dark energy can be derived from Dirac's relativistic equation as the negative square root of [itex] E^2 = c^2 \vec{p}^2 + m^2 c^4[/itex].
     
    Last edited: Jul 28, 2004
  11. Jul 28, 2004 #10
    Microstates justs means different energy levels much as a group of atoms is composed of individual atoms at different levels of excitation.
     
  12. Jul 28, 2004 #11
    These energy levels must be the complex conjugate of the energy operator in the relativistic wave equations.
     
  13. Jul 28, 2004 #12
    Excitations are not stable. Excited atoms seek stability by quickly radiate photons.
     
  14. Jul 28, 2004 #13
    What information does this complex conjugate of the energy operator carry in relativistic quantum mechanics - any information about dark energy is useful information to me.I expect dark energy to be non-uniform because if it can come from other energy sources in the universe, then since no other enrgy source in the universe can be uniformly distributed throughout it,dark energy shouldn't be either.
     
  15. Jul 28, 2004 #14
    You haven't accepted which geometry you are going to use then?
     
    Last edited: Jul 28, 2004
  16. Jul 28, 2004 #15
    This was already used by Dirac to explain the existence of antimatter.
     
  17. Jul 28, 2004 #16
    If you limit yourself to SR approaches, you limit yourself to further explanations on the nature of the geometries. If you join electromagnetism and Gravity, there is a result theoretically, and a geometry, that helps you move forward.

    You use Dirac yes, but its gone much further then this. :smile:
     
  18. Jul 28, 2004 #17
    sol2,

    Dirac could not give any geometric interpretation. The best he did was the sea of negative energy.

    My interpretation for [itex]E^2[/itex] is the existence of two distinct topologies of fully twisted Moebius strip. And with your suggestion, and I already mentioned in other posts, the spin is related to the genus of the topologies.
     
  19. Jul 28, 2004 #18
    My interpretation of [itex] E^2 [/itex] is that it can also be given by

    [tex]E^2 = \psi_i \times \phi_i \cdot \psi_j \times \phi_j [/tex]

    When for time independency, [itex] \psi [/itex] is the wave function of QM and [itex] \phi [/itex] is the conjugate variable of momentum.
     
  20. Jul 28, 2004 #19
    I think, at first many physicists, no doubt, thought that dark energy should come from antimatter. But the problem is antimatter cannot be found globally. Locally, it happens at quantum fluctuations of the vacuum and high energy domains in particle accelerators. But the vacuum is highly uniform because of the isotropy and homogeneity of the cosmos regardless of the existence of stars and galaxies and other interstellar or intergalactic gases and nebulae.
     
  21. Jul 28, 2004 #20
    Antimatter cannot be found globally if nearly all of it has already become dark energy.
    This suggests the universe will stop accelerating soon and the dark energy density
    will decrease as antimatter reforms from dark energy.
     
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