Reason for matter rather than antimatter?

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Discussion Overview

The discussion revolves around the question of why the universe appears to be composed predominantly of matter rather than antimatter, exploring concepts related to particle/antiparticle creation during the inflation period and vacuum energy density. The scope includes theoretical considerations and speculative reasoning about cosmological phenomena.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant suggests that during the inflation period, the inflaton field decays into particle/antiparticle pairs, with one particle traveling forwards in time and the antiparticle traveling backwards, potentially explaining the predominance of matter.
  • Another participant challenges the claim about the total 4-momentum of the pair being zero, asserting that energy must exceed zero for particle creation, and questions the implications of negative energy for antiparticles.
  • A different participant introduces the idea that if the vacuum energy density had a higher energy scale in the past, electron pairs could have been created spontaneously, with one electron having positive energy and the other negative, which might explain the absence of negative-energy primordial positrons.
  • One participant reiterates the initial claim about particle/antiparticle pairs and adds a perspective that if we were made of antimatter, we would refer to matter as antimatter, emphasizing a viewpoint on perspective.
  • Another participant disputes the notion that vacuum energy can be considered the zero-point of energy measurement in this context, dismissing the speculative nature of the arguments presented.

Areas of Agreement / Disagreement

Participants express disagreement on several points, particularly regarding the nature of particle/antiparticle creation and the implications of energy measurements. The discussion remains unresolved with multiple competing views presented.

Contextual Notes

Limitations include assumptions about the inflation period, the nature of vacuum energy, and the implications of negative energy, which are not fully explored or agreed upon by participants.

jcap
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At the end of the inflation period (if it occurred) the potential energy of the inflaton field decays into particle/antiparticle pairs.

When a particle/antiparticle pair is created each component of the total 4-momentum of the pair is zero. This must include the time component as well as the spatial components.

Thus one member of the pair travels forwards in time (the particle with positive time-momentum/energy) and the other travels backwards in time (the antiparticle with negative time-momentum/energy).

As we are made of particles going forwards in time could this be the reason why we only see particles in the universe?
 
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When a particle/antiparticle pair is created each component of the total 4-momentum of the pair is zero.
That's not correct. The production needs at least twice the mass of the particles as energy, that is larger than zero.
Thus one member of the pair travels forwards in time (the particle with positive time-momentum/energy) and the other travels backwards in time (the antiparticle with negative time-momentum/energy).
Even if the above would be right that wouldn't be correct either. It would mean some particles have negative energy, which is not what we observe.
jcap said:
As we are made of particles going forwards in time could this be the reason why we only see particles in the universe?
No.
 
Using cosmological measurements the vacuum energy density is estimated to have an energy scale of ##T=(\rho_{vac})^{1/4}=10^{-3}## eV.

But as far as we know it could have had an energy scale in excess of ##1.02## MeV in which case pairs of electrons could be created spontaneously out of the vacuum.

I know that the vacuum energy density is constant but for the sake of argument assume that somehow in the distant past the vacuum had an effective local energy scale of ##T=1.02## MeV.

Now as far as I understand it the vacuum energy scale can be taken to be the zero-point of energy measurement.

Thus one could say that in the distant past electron pairs were created spontaneously out of zero energy.

In that case one electron has positive energy/time-momentum and travels forwards in time whereas the other electron has negative energy/time-momentum and travels backwards in time.

This would explain why, at the present time, we only see positive-energy primordial electrons and not negative-energy primordial electrons (positive-energy primordial positrons).

Would this make sense?
 
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jcap said:
At the end of the inflation period (if it occurred) the potential energy of the inflaton field decays into particle/antiparticle pairs.

When a particle/antiparticle pair is created each component of the total 4-momentum of the pair is zero. This must include the time component as well as the spatial components.

Thus one member of the pair travels forwards in time (the particle with positive time-momentum/energy) and the other travels backwards in time (the antiparticle with negative time-momentum/energy).

As we are made of particles going forwards in time could this be the reason why we only see particles in the universe?
If we were made from antimatter, then we would refer to matter as antimatter. It's all about perspective
 
jcap said:
as far as I understand it the vacuum energy scale can be taken to be the zero-point of energy measurement

No, it can't, not in this context.

jcap said:
Would this make sense?

No. It's personal speculation. Personal speculation is not allowed at PF. Thread closed.
 

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