Initial state of the Universe?

[mathman]

[Moderator's note: Spin off from previous thread due to topic/level change.]

Although the initial state of the universe is subject to much speculation, it seems to have started as all (or almost all) energy with particles being created out of photon-photon interactions.

 

[PeterDonis]

Although the initial state of the universe is subject to much speculation, it seems to have started as all (or almost all) energy with particles being created out of photon-photon interactions.

No, the initial state (or at least the earliest state for which we have good evidence, the state right after "reheating" at the end of inflation in inflation models) was a state in which all of the Standard Model fields had a large energy density--quarks, leptons, and gauge bosons--not just photons. In fact, "photons" as we know them today didn't even exist then, because the energy was far above the electroweak symmetry breaking energy and the "photon" we know today only existed after electroweak symmetry breaking occurred.

 

[PeterDonis]

all (or almost all) energy

"Energy" does not name a state. It names a property that all states have.

 

[mathman]

No, the initial state (or at least the earliest state for which we have good evidence, the state right after "reheating" at the end of inflation in inflation models) was a state in which all of the Standard Model fields had a large energy density--quarks, leptons, and gauge bosons--not just photons. In fact, "photons" as we know them today didn't even exist then, because the energy was far above the electroweak symmetry breaking energy and the "photon" we know today only existed after electroweak symmetry breaking occurred.

My speculation is about condition before inflation.

 

[PeterDonis]

My speculation is about condition before inflation.

Then you will need to give a reference because I am not aware of any model that describes conditions before inflation the way you described them. In fact, in eternal inflation models, which are the current front-runner, there is no such thing as "before" inflation at all.

(If you have no reference then your post is personal speculation and is off limits for PF.)

 

[mathman]

No, the initial state (or at least the earliest state for which we have good evidence, the state right after "reheating" at the end of inflation in inflation models) was a state in which all of the Standard Model fields had a large energy density--quarks, leptons, and gauge bosons--not just photons. In fact, "photons" as we know them today didn't even exist then, because the energy was far above the electroweak symmetry breaking energy and the "photon" we know today only existed after electroweak symmetry breaking occurred.

From Wikipedia:​

​

Inflation and baryogenesis​

Main articles: Inflation (cosmology) and Baryogenesis
The earliest phases of the Big Bang are subject to much speculation, since astronomical data about them are not available. In the most common models the universe was filled homogeneously and isotropically with a very high energy density and huge temperatures and pressures, and was very rapidly expanding and cooling. The period from 0 to10^{−43} seconds into the expansion, the Planck epoch, was a phase in which the four fundamental forces — the electromagnetic force, the strong nuclear force, the weak nuclear force, and the gravitational force, were unified as one.[25] In this stage, the characteristic scale length of the universe was the Planck length, 1.6×10^{−35} m, and consequently had a temperature of approximately 10^{32} degrees Celsius. Even the very concept of a particle breaks down in these conditions. A proper understanding of this period awaits the development of a theory of quantum gravity.[26][27] The Planck epoch was succeeded by the grand unification epoch beginning at 10^{−43} seconds, where gravitation separated from the other forces as the universe's temperature fell.[25]

 

[PeterDonis]

From Wikipedia:​

As an SA you should be well aware that Wikipedia is not a valid reference. (Also, you don't even give a link to the actual article you're quoting from.)

Since we do not have a valid theory of quantum gravity, or even a valid theory of grand unification (unification of all three of the interactions in the Standard Model), claims about the Planck epoch and the grand unification epoch are speculative, and discussion of them belongs in the Beyond the Standard Model forum. [Moderator's note: And I have just spun this sub-thread off into a separate thread in that forum.] (Also, even in that [Edit: this] forum, references should be to actual peer-reviewed papers, not Wikipedia articles.)

In any case, what you quote from Wikipedia still does not match what you claimed in post #9:

Although the initial state of the universe is subject to much speculation, it seems to have started as all (or almost all) energy with particles being created out of photon-photon interactions.

This does not describe any of the epochs (speculative as they are) described in the Wikipedia quote you gave. Nor does it describe inflation or baryogenesis.