Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Quantum gravity force violations

  1. Jul 8, 2004 #1
    Apart from C, P and T violation in weak interaction, do the same violations occur for the other three forces, in particular, the quantum gravity force?
    Last edited: Jul 8, 2004
  2. jcsd
  3. Jul 8, 2004 #2
    Both EM and strong force respect C, P and T. I am pretty certain that gravity also respects them: a particle has the same mass as its antiparticle so its gravitational pull is the same (C). I think Einstein's equations are time reversal invariant so (T) holds, hence (P) should also hold by CPT.
  4. Jul 8, 2004 #3
    Why then is the weak force the only force to violate C, P and T symmetry? Isn't that funny?
  5. Jul 8, 2004 #4


    User Avatar
    Science Advisor

    The answer is that experiment demands it..

    So by construction the theory is chiral, eg its a guage theory in the yangmills sense with two representations of SU(2)

    Su(2) (left) * Su(2) (right)
  6. Jul 9, 2004 #5


    User Avatar
    Staff Emeritus
    Gold Member
    Dearly Missed

    And that is because SU(4) the double cover of the Poincare group, just happens to decompose into two copies of SU(2), so the 4-component spinors have their first two components acted on independently of their last two. Left and right helicity.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook