CPT-symmetry is our universe's symmetry. Today's physics believes that every change or interaction in particle physics is CPT-sy...
CPT-symmetry is our universe's symmetry. Today's physics believes that every change or interaction in particle physics is CPT-symmetric. It is more than a belief, it is a postulate about our universe symmetry, our universe is CPT symmetric. If it were not true, we would be live in a different world, not what we are experiencing. However, we are living in a strange universe too, an asymmetric one where only one type of matter is the dominant and overwhelmingly more than the other kind, called antimatter.
It was a hint in earlier thought, where this matter-antimatter asymmetry would come from. Let's see it in a more detailed thought. First about the CPT-symmetry.
CPT is a complex symmetry with different parts. The C is the charge conjugation, and it is related to the matter-antimatter symmetry. It means if we change every matter particles to its antimatter counterparts, the universe will look the same. This symmetry is an easily understandable one, because every particle experiment where matter created from energy, the antimatter counterparts always appears with the matter particles.
C-symmetry explains a lot of our physical laws and its symmetry, however, leave the question open, why our universe consists only of matter. There are some suggestions for this asymmetry. Maybe in the early universe, where this asymmetry possibly originated, the physical laws were different or at that high energy of the early universe, the same laws that we have now behaved differently. Still no widely accepted theory to the matter-antimatter asymmetry. Anyway, the C symmetry was thought of as it is the symmetry of the universe, until...
It tells a lot about our universe that C is not a perfect symmetry of the universe. It was thought until physicists learned enough about the neutrino and the weak interaction. Recognized that the C-symmetry, the matter-antimatter symmetry cannot be applied to the weak interactions. As the experiments showed, there is a fundamental difference between the neutrinos and antineutrinos created in the weak interactions. They are different in spin, a kind of internal attribute related to a rotational momentum. As it was experienced, the weak interaction always creates neutrinos and antineutrinos with the same and opposite spins. Neutrinos have a clockwise spin, antineutrinos have counterclockwise. Always. They are mirror images of each other. Because neutrinos created only by the weak interactions, the matter cannot be interchanged simply with antimatter or at least in the case of neutrinos. This symmetry called P, parity inversion, mirror symmetry. Only in a special instance, still, the C-symmetry is not a perfect symmetry of the universe.
P-symmetry is an interesting symmetry, like chirality in chemistry. It means the physical laws, which are governing our universe, in some cases distinguish between the left and the right, it has mirror symmetry. That is strange, it shows a lot, but OK, acceptable, we are living in this kind of universe.
As experiments showed, the universe has no perfect symmetry switching between matter-antimatter and has no perfect symmetry simply mirroring everything either. However combining both symmetries, exchanging everything to its anti-counterparts and seeing everything from a mirror also could be the symmetry of the universe, no noticeable difference in the behavior of the two universes. They are not the same, but all the physical laws would work the same way in both cases so our universe could be the other, we could not notice the difference.
The two universes are not the same, even if the physical laws are working the same way. If one dominated by matter, the other would dominate in antimatter. However, the two, the combined CP-symmetry still not an explanation of why is there a kind of domination. The CP-symmetry cannot create the difference between the balances of the two matter type.
These two symmetries are a kind of static symmetry. Applying it to our universe as a one-fold event, do it in an instant, and we will have an entirely similar universe. Of course, it is only a theoretical transformation, we could not do it in practice, but if this instant happened, everything would go how it went before. Every interaction, every movement would be the same. Our life would not change a bit at this moment, we couldn't even notice it. Our life would carry on without a hitch, unnoticed the change.
The CP-symmetry is a beautiful symmetry. It does not explain the difference between the two types of matter, but it shows a lot about our universe. And, as it was found out, the CP-symmetry still not the perfect symmetry of our universe. Something still needed.
Time is a strange thing. It behaves as a kind of dimension. Sometimes it can be reversed, sometimes not. It cannot be stopped, but for some particles, it not starts at all. According to some theories, like loop quantum gravity or the grid model, time not even exists.
In particle physics, every change can go backward. If there is a particle interaction, it can go in either direction, back or forth, both ways are possible. The particle interactions do not distinguish between the flow of the time, or at least if the time went in backward, the interactions would happen in the opposite directions, all those interactions would be valid. The particle interactions are time- or would say direction-independent.
It was the belief until the long-lived neutral kaon decay observed. This kaon decay showed that CP is not a perfect symmetry of the universe either, because when the CP counterpart of the mentioned kaons decay, it decays differently according to the direction of time, so the CP counterparts can be distinguished.
The time, or at least its direction as changes happen carry an important role in the subject of our physical law's symmetry, how should our universe be transformed into another to behave like ours. As experiments showed the mentioned kaon decay violates the CP-symmetry, as some difference in the decay between the CP-symmetric kaon counterparts. And even violates the T symmetry as well, as a small difference between the back or forth directions of the decay of these kaons experienced. However, applying all the three symmetry, CPT, so change every particle to its anti-pair, change all space directions to its reverse and reverse all interactions backward or as its equivalence, change all momentum and angular momentum to its opposite counterparts, so reverse the time would work. These transformations together would create another universe that could not be distinguished by physical laws from ours.
The mentioned kaon decay, from where the CPT-symmetry originated, does not say why is this T-asymmetry, just showing it, states that CPT-symmetry would be correct.
We arrived, we found our universe's perfect symmetry. The CPT-symmetry would create a universe with the same physical laws that our universe has. However, even the CPT-symmetry cannot explain the difference between why one type of matter dominant.
All the physical laws that examined, what created the CPT-symmetry rule acted locally. These physical laws are valid in the whole universe, but its actions, where it acts actually happen limited to a given and small parts of the universe, to space where particle interactions actually happen. These physical law's actual act always confined into a limited space, directly does not affect the whole universe. The physical laws are locally CPT-symmetric, and as physical laws are acting locally, it creates our CPT-symmetric universe.
However, what if the matter-antimatter difference is not a locally acting asymmetry but connected to an asymmetry which is a global one. As we saw, our locally acting physical laws do not create an asymmetry between the two types of matter, or at least according to our current knowledge. What if this asymmetry is created by a global property of our universe, a kind of physical law, which act globally, has the effect to the whole universe? If this global physical property has a kind of asymmetry, it could create a matter-antimatter difference.
The T-symmetry in some way differs from the other two. It is a kind of dynamic symmetry. If we apply only the CP-symmetry to our universe, we would not even notice that anything changed. Our life, like everything else, would go on in the same way as before. However, we saw that CP is not a perfect symmetry of our universe, the universe created by the CP-symmetry would differ from ours. We need the time transformation to be applied as well. And that transformation would create a very strange world. The world where everything is going suddenly backward. The T-symmetry changes every particle interactions in its opposite direction, so what happened before suddenly will happen again, and before that, and before that. The time would flow backward, every change that happened, happen again in backward order. The flow of the time is reversed.
Time has another aspect than other physical laws. It can act globally, not just locally. In the local sense, it reverses the directions of particle interactions, but time can act in a global sense as its flow affects the whole universe. Time acts as a global player too.
However, time has its problem by itself. Very difficult to originate directly from any physical entity. It's not like weight, speed or even color, time is very elusive.
What if the time, as some theories suggest, does not exist at all? Would be no physical existence of time dimension, and everything that we described as time needs to be described again without using the time as a physical entity. Let's suppose, time, as an independent physical entity does not exist. Suppose, time is a good and useful concept to describe the physical states, but itself, as physical reality does not exist. Then we must explain the time, and it's symmetry without the time itself.
The time describes the change and movement. Time's origin must be in these physical entities. Let's try to describe the time and its symmetry with these entities. Then the time and its symmetry are not about the time itself, but about the change and movement (which was used in the description of the T-symmetry anyway). What does it mean? If we use movement and change for the description instead of the time, we will have actual physical entities for the description. This method would have a useful aspect. We could describe the time as not just a local phenomenon by the movement and the change, but its global meaning too, as movement and change can act globally as well.
Let's see the T-symmetry in this framework. Then we are not talking about reversing the time, but reversing all the movement to its direct counterparts. It is possible because every interaction and movement can go backward in the sense of the CPT symmetry. We could describe our universe's laws and its symmetry applying change and movement without using the concept of the time.
Time in this sense can be obsolete by replacing it with the description of the change and movement, the CPT symmetry would stay valid with this switch. All the symmetry would remain valid. And still no answer to the matter-antimatter asymmetry either.
However, this switch of the theoretical viewpoint allows two different kinds of movement and symmetry. One is the local change and movement which still symmetric, but there is another, a global movement. If the global movement of the universe is asymmetric, it can create a global asymmetry which can cause the matter-antimatter difference.
What this global movement which affects our whole universe could be? If our universe had a kind of displacement, it would create the matter-antimatter asymmetry. How?
What kind of movement, what kind of displacement could the universe have to provide the matter-antimatter asymmetry? As we saw, the movement providing the matter-antimatter difference must be global. But related to what? In what dimension? Could it be in our regular three space dimensions or is it in something else?
If the matter-antimatter asymmetry originated in the global displacement of our universe, then this displacement would create some kind of physical footprint, other than the matter-antimatter asymmetry too, what we would notice it already. Special relativity theory states all the physical laws remain the same if we are moving at a constant speed. The global displacement is hard to notice inside from the moving system, and it even keeps all the symmetry the same. However, if our universe is or was moving with changing speed, it still would provide some kind of trace that we could already notice it.
The evidence of the rotation in regular space dimensions could be significant. For example, a rotating universe, which rotates in the regular space dimensions, a Gödel's universe, has closed space-time loops. It is possible to travel back in time in these universes. Hopefully, our universe isn't such a kind.
We have pieces of evidence that our physical laws are the same even back in billions of years, and these physical laws prevent travels to back in time. This global movement, which may create the matter-antimatter asymmetry may not be in the regular space dimensions.
What kind of movement would we have and would be possible, which even can act globally and is not in our regular space dimensions? This movement must be subtle, maybe inner kind but still can be global.
According to the physical theory of the grid model, our physical world exists as a vibration of a grid field consisting of grid particles. If these particles' vibrations are synchronized, it creates patterns, waves on the grid field, which are the particles of our world. If the synchronized vibration creates a closed-loop, it is a particle type of fermion, if not, it is a boson.
If the grid model is valid, the loops creating the fermions in the grid model may provide the space dimension in where the global displacement of our universe may occur. These loops, which are explicitly applied to the fermions, have an inner kind of origin, similar to or the same as what we are experiencing as the spin of the particles. If our universe would have a global movement in a spin like direction, rotating in a direction as the loop structure suggests, it may provide the global matter-antimatter asymmetry. The matter-antimatter asymmetry then originated in a global rotation of the universe, and the asymmetry may be a kind of Doppler effect of this rotation.
The particles that rotations are in the directions of the whole universe's rotation would be favored instead of the particles with the opposite rotational direction. The difference in the asymmetry is in a relationship with the global rotation and this way may be calculable.
In our current scientific view, the matter-antimatter asymmetry originated only in the early universe. It most likely true, if this asymmetry's origin is in the locally acting physical laws. It would cause theoretical problems about our physical laws' symmetry and how our physical laws work if it would be originated otherwise. However, if the matter-antimatter asymmetry is originated in a global asymmetry of a property of the universe, like displacement or rotation, then the theoretical problems of the local symmetry of our physical laws would vanish.
How about the acting time of the effect? This global asymmetry may have appeared only in the early stages of the universe, but it could be present actually too, and it may be provable by experiments.
This thought has a lot of ifs, maybes, but still worth to think about it.
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