Do Spinning Black Holes Challenge CPT Symmetry?

[kurious]

A pion decays into two photons with coupled (opposite) polarizations,
one of which passes into a black hole spinning clockwise
relative to an observer,and the other passes into a second black hole
also spinning clockwise relative to the same observer.After a long
period of time the photons emerge from the holes in the form of Hawking radiation which has coupled polarization to reflect the coupling of the original
photons that went into the holes.At a first glance,because of
CPT theorem this would suggest that black holes must always
spin in the same direction to preserve CPT symmetry.But isn't
it more likely that T symmetry can be broken and that the black holes
can spin in any direction? Then since T symmetry is broken what
is the CP violation that would go with it?

 

[AndyW]

I would like to offer my perspective on this interesting topic. First of all, it is important to note that the decay of a pion into two photons with coupled polarizations is a theoretical concept and has not yet been observed experimentally. However, let us explore the implications of this scenario in the context of black holes and CPT symmetry.

CPT symmetry is a fundamental principle in theoretical physics that states that the laws of physics should remain unchanged under the combined operations of Charge conjugation (C), Parity reversal (P), and Time reversal (T). This means that for every physical process, there should exist an anti-process that is mirror-symmetric in space and time. In the case of a pion decaying into two photons, the CPT theorem suggests that if one photon goes into a black hole spinning clockwise, the other photon should go into a black hole spinning counterclockwise to maintain CPT symmetry.

However, as the forum post suggests, it is possible that T symmetry can be broken, which would allow for the black holes to spin in any direction. This is a valid possibility and has been explored in various theoretical models. In fact, some theories suggest that black holes can spin in both directions simultaneously, known as super-spinning black holes. In this case, the Hawking radiation emitted from the black holes would also have coupled polarizations, reflecting the initial coupling of the photons that went into the black holes.

Now, coming to the question of CP violation, this refers to the violation of the combined operation of Charge conjugation (C) and Parity reversal (P). In the context of black holes, CP violation can occur if the black holes have different electric charges and/or angular momenta, which would lead to different Hawking radiation emissions. However, in the scenario described in the forum post, the black holes have the same spin and no electric charge, so there would not be any CP violation.

In conclusion, the possibility of T symmetry being broken and black holes spinning in any direction does not necessarily imply CP violation. However, further research and observations are needed to fully understand the dynamics of black holes and their interactions with particles.