Empirical evidence for two arrows of time

https://www.facebook.com/profile.php?id=61579273676681 Source: Perimeter Institute for Theoretical Physics Canada, European Space Agency Planck Collaboration, Physical Review D, 2025 \subsection{Evidence that the Universe has two arrows of time} The scientists in Perimeter Institute for Theoretical Physics Canada and European Space Agency Planck Collaboration have published in Physical Review D, 2025 evidence that the Universe has two arrows of time. The presence of two arrows of time is claimed to correspond to hemispherical asymmetry of the CMB. It is not obvious to me why the presence of two arrows of time would reflect itself via this asymmetry.

Could these findings be interpreted as a support for the zero energy ontology (ZEO) of TGD predicting that two arrows of geometric time are possible and that roughly one half of the Universe has both arrows of time?

1. In TGD, the view about the arrow of geometric time is more complex than in the framework of standard cosmology. The arrow of geometric time is associated with a given causal diamond (CD), which is analogous to a sub-cosmology in a Russian doll cosmology defined by a hierarchy of CDs with increasing size scales. A given CD can have both arrows of time and the arrow of time changes in the TGD counterpart of ordinary quantum measurement. The hierarchy of effective Planck constants labelling an infinite hierarchy of quantum coherence scales, which correspond to the size scales of the space-time surfaces and of CDs, is essential.
2. The meaning of the arrow of time used by the researchers is based on CPT as a symmetry. The proposal is that CPT would relate the two Universes with an opposite arrow of time: CPT would not be a trivial operation anymore. On the other hand, the time reversal in the sense of TGD inspired theory of consciousness does not reduce to time reversal as a discrete symmetry although one cannot exclude the possibility CPT - and TGD based views are closely related. It is assumed that the two arrows of time correspond to two half-cones of the light-cone. In the TGD framework, they would correspond to the two halves of a causal diamond CD as an intersection of future and past directed light-cones.

The TGD view of the arrow of time means roughly the following.

1. In quantum field theories there are two vacua as states annihilated by annihilation resp. creation operators. In the original picture of Dirac, all positive/negative energy states of fermions would be filled for these two vacua. In the standard QFT only the second vacuum is selected.
2. In TGD, a new quantum ontology, zero energy ontology (ZEO), solving the basic problem of quantum measurement theory, is forced because the classical time evolutions fail to be strictly deterministic. This non-determinism is absolutely essential for the non-triviality of quantum TGD and also for the TGD inspired view of consciousness. The mild non-determinism forces us to introduce additional discrete degrees of freedom implying that one must allow 3-D seats of classical non-determinism as carriers of quantum numbers in the interior the 4-D space-time surface obeying almost deterministic holography identified as cognitive degrees of freedom not present in standard physics.
3. In ZEO 3-D quantum states are replaced by zero energy states. In fermionic degrees of freedom, zero energy states in fermionic degrees of freedom correspond to pairs of 3-D many-fermion states assignable to the intersections of space-time surfaces with the opposite light-like boundaries of causal diamonds (CDs). These 3-D quantum states could be interpreted as initial and final states of a slightly non-deterministic time evolution. At the level of space-time surfaces, zero energy states are quantum superpositions of Bohr orbit-like space-time surfaces satisfying holography = holomorphy principle.
4. The states at the passive boundary of CD are unaffected by time evolution as small state function reductions (SSFRs). SSFRs define a generalization for a sequence of measurements of fixed observables. In standard QM these sequences leave the quantum state invariant meaning Zeno effect. In TGD, the Zeno effect is replaced with a sequence of SSFRs defining a flow of consciousness, self. In SSFR, the active boundary of CD is shifted, CD increases in statistical sense and the passive boundary suffers only a scaling leaving the 3-D quantum states at it invariant.
5. "Big" state function reduction (BSFR) is the counterpart of ordinary state function reduction. BSFR changes the roles of passive and active boundaries of CD so that the arrow of time is changed. At the level of conscious experience BSFR means death/falling asleep of self at a given level of self hierarchy.
6. In the TGD Universe, quantum coherence is possible in arbitrarily long scales. In cosmic scales stars older than the Universe can be explained by ZEO. Stars older than the Universe is an example of possible consequences of ZEO in cosmic scales.

See for instance, this, this and this.