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Old 04-09-2010, 12:58 PM
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sjastro
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Quote:
Originally Posted by CraigS View Post
So Steven;
If:
- symmetry under translation corresponds to conservation of momentum and;
- symmetry under rotation to conservation of angular momentum and;
- symmetry in time to conservation of energy, e,

have they figured out which symmetry broken system is thought to have caused the Big Bang ?

Cheers
In these examples the symmetry hasn't been broken. A mathematical operation such as translation, rotation etc results in the Lagrangian (which describes the energy of the system) to remain the same (it is invariant).

In QFT there is Gauge Theory. Gauge theory predicts the existence of zero mass gauge bosons such as photons. Gauge bosons are required in order for the Lagrangian to remain invariant, but cannot predict bosons with mass such as the W, Z and the yet to be discovered Higgs boson.

By breaking the symmetry gives mass to the bosons. The theoretical properties of the W and Z bosons as predicted by symmetry breaking were confirmed after their discovery.

With regards to the BB a gauge field may have existed prior to the BB, but as to what symmetry may have been broken to trigger the BB no one knows.

M (brane) theory also predicts a pre BB.

Regards

Steven

Last edited by sjastro; 04-09-2010 at 01:09 PM.
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