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Tuesday, 24 November 2009 01:48 |
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One of the reasons our physics is incomplete during the Planck era is a lack
of understanding of the unification of the forces of Nature during this time.
At high energies and temperatures, the forces of Nature become symmetric.
This means the forces resemble each other and become similar in strength,
i.e. they unify. When the forces break from unification (as the Universe
expands and cools) interesting things happen.
- the development of the macroscopic world begins with the first symmetry breaking era, between quantum and
gravity forces
- later breaks set down the behavior of matter
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An example of unification is to consider the interaction of the weak
and electromagnetic forces. At low  energy, photons and W,Z particles
are the force carriers for the electromagnetic and weak forces. The
W and Z particles are very massive and, thus, require alot of energy
(E=mc2). At high energies, photons
take on similar energies to W and Z particles, and the forces become
unified into the electroweak force.
There is the expectation that all the nuclear forces of matter (strong,
weak and electromagnetic) unify at extremely high temperatures under a
principle known as Grand Unified Theory, an extension of quantum physics
using as yet undiscovered relationships between the strong and electroweak
forces.
The final unification resolves the relationship between quantum forces
and gravity (supergravity).
In the early Universe, the physics to predict the behavior of matter is
determined by which forces are unified and the form that they take.
The interactions just at the edge of the Planck era are ruled by
supergravity, the quantum effects of mini-black holes. After the
separation of gravity and nuclear forces, the spacetime of the Universe is
distinct from matter and radiation. |
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