The mirror Universe hypothesis of Turok and Boyle from the TGD point of view

The popular article 'Cosmic inflation:' did the early cosmos balloon in size? A mirror universe going backwards in time may be a simpler explanation by Neil Turok, tells about the proposal of Neil Turok and Latham Boyle stating that the early Universe effectively contained the CP, or equivalently T mirror image, of the ordinary Universe and claims that this hypothesis solves some problems of the cosmology.

The article contains some mutually conflicting statements related to the interpretation of time reversal: I don't know whom to blame.

What is meant with time reversal?

Time reversal has two different meanings, which are often confused. It can refer to time reflection or change of the arrow of time. This confusion appears also in the article.

1. The article states that T refers to a time reflection symmetry. The article also states that time flows backwards in the mirror universe. These two statements are not consistent. Either the authors or the popularizers have confused T and time reversal in thermodynamic sense.
2. The arrow of time is fixed in standard QFT and therefore in thermodynamics. In quantization this means a selection of vacuum. What we call annihilation operators, annihilate the vacuum. For the other option, their hermitian conjugates would annihilate the vacuum with the opposite arrow of time.
3. In the zero energy ontology (ZEO) of TGD, these arrows of time are associated with quantum states, which remain unaffected at the passive boundary of CD in the sequence of "small" state function reductions. This time reversal has nothing to do with T or CP. "Big" SFRs (BSFRs) change the roles of active and passive boundaries and change the arrow of time. These two arrows of time are in a central role in the TGD inspired cosmology and also in biology.
4. Could the ordinary matter in phases with opposite arrows of time behave like a mirror universe? The arrow of time changes in BSFRs and means a death or falling asleep of a conscious entity. By a simple statistical argument half of the matter is ordinary and time reversed "sleep" states (half of the universe "sleeps"). Note that there is a scale hierarchy of conscious entities.

   The phases of matter with opposite arrows of time cannot see each other by classical signals. The detection process requires what is essentially pair creation of fundamental fermions. One could therefore say that in TGD the mirror universe exists in a well-defined sense.

5. In fact, the change of arrow of time in BSFRs is possible in arbitrarily long scales due to the hierarchy of Planck constant making quantum coherence possible even in astrophysical scales. This implies that the evolution of astrophysical objects is a sequence of states with opposite arrows of time. Living forth and back in geometric time implies that their evolutionary age is much longer than the geometric age and this explains stars and galaxies older than the universe.

2. Problems related to the mirror universe hypothesis

1. Suppose the mirror image in the theory of Turok et al is indeed T mirror image. One must explain why it is invisible for us. The proposal is that the mirror universe might be a mere mathematical trick. This makes me feel uneasy.
2. In the proposed model the mirror image would consist mostly of antimatter and the unobservability of the mirror universe would apparently solve the problem due to matter antimatter asymmetry. This does not however solve the problem why there the amount of matter/antimatter in the universe/its mirror is so small. One must explain why CP breaking leads to this asymmetry.

   The TGD explanation of matter antimatter asymmetry suggests that antimatter is confined within cosmic strings and matter outside them and that the decay of the cosmic strings to ordinary matter as a counterpart of the inflation process violates CP symmetry and leads to the asymmetric situation.

3. Can the hypothesis solve the problem of dark matter?

The proposed hypothesis states that dark matter consists of right handed neutrinos and that they interact with ordinary matter only gravitationally.

1. The problem is that the standard model does not predict right-handed neutrinos so that the mirror universe would contain only the antiparticles of left handed neutrinos which would interact and would not be therefore be dark. Standard model should be modified.
2. In TGD, right-handed neutrinos are indeed predicted and their covariantly constant modes would behave like dark matter. Covariantly constant right handed neutrinos are the only massless spinor modes of M⁴×CP₂ spinors but might mix with higher massive color partial waves. They could also represent an analog of supersymmetry. In TGD ν_R:s would appear as building bricks of fermions and bosons. Can ν_R:s exist as free particles? Number theoretic vision and Galois confinement suggests that this is not possible. Therefore ν_R:s would not solve the problem of galactic dark matter.

   In TGD the dark (magnetic and volume) energy of cosmic strings explains galactic dark matter but one cannot of course exclude the presence of right handed neutrinos and other fermions inside cosmic strings. Whether quantum-classical correspondence is true in the sense that the classical energy of cosmic strings actually corresponds to the energy of fermions inside them, remains an open question.

4. Does the mirror universe solve the entropy problem

It is also claimed that the mirror universe solves the problem related to entropy. On basis of the popular article I could not understand the argument.

1. Second law suggests that the very early Universe should have a very low entropy. This is in a sharp conflict with radiation dominated cosmology.
2. In TGD this is not so simple, since both arrows of time are possible and both thermodynamics are possible and time reversed dynamics increases entropy in the opposite direction of geometric time so that it apparently decreases in the standard arrow of time. This effect is actually used to reduce the entropy of phase conjugate laser beams.

   In TGD however the very early Universe would consist of cosmic strings which would make collisions (here the dimension of space-time is crucial) causing their thickening and transformation to ordinary matter. This would lead to radiation dominated cosmology.

   But what is the entropy of the cosmic string dominated phase? The cosmic string dominated phase could have a very low entropy if the geometric excitations are absent (note that cosmic strings are actually 3-D and only effectively 1-D). The number of excited states (deformations) of the string increases rapidly with temperature. This implies Hagedorn temperature as a maximal temperature for cosmic strings.

   Was the very early Universe in Hagedorn temperature or was it heated from a very low temperature to Hagedorn temperature and made a transition to a radiation dominated phase by the thickening to monopole flux tubes and subsequent decay to ordinary matter? If I must make a guess I would say that the temperature was very low.

See the article Latest progress in TGD or the chapter with the same title .

For a summary of earlier postings see Latest progress in TGD.

For the lists of articles (most of them published in journals founded by Huping Hu) and books about TGD see this.