The world of the new Boussois theorem always deviates from our universe notably. For mathematical convenience, he assumed that there is an unlimited variety of particles – an unrealistic hypothesis which makes some physicists wonder if this third layer corresponds to reality (with its 17 known particles) better than the second layer. “We have no infinite number of quantum fields,” said Edgar ShaghoulianPhysicist at the University of California, Santa Cruz.
However, for some experts, Bousso’s work offers a satisfactory outcome of the history of the singularity of Penrose and Wall, despite its unrealistic abundance of particles. It establishes that singularities cannot be avoided, even in spatial time with mild reactions to quantum matter. “Just by adding small quantum corrections, you cannot prevent singularity,” said Penington. Wall and Bousso’s work “responds to this subject quite definitively”.
The real singularity
But Bousso’s theorem still does not guarantee that singularities must form in our universe.
Some physicists hope that the dead ends disappear in a way. What seems to be a singularity could actually connect elsewhere. In the case of a black hole, perhaps these light rays are found in another universe.
And the lack of singularity of the big bang could imply that our universe began with a “big rebound”. The idea is that a previous universe, while it collapsed under the attraction of gravity, somehow dodged the formation of a singularity and rather rebounded in a period of expansion. Physicists who develop the theories of rebound often work in the second layer of the onion, using semi-classical physics that exploits Quantum effects of negative energy To bypass the singularity required by Penrose and Hawking theorems. In the light of new theorems, they will now have to swallow the uncomfortable truth that their theories also violate the second generalized law.
A physicist who pursues the rebounds, Surjeet Rajendran From Johns Hopkins University, says it is not introduced. He underlines that even the second general law is not the evangelical truth. Rejecting it would make the singularities avoidable and the continuations of space-time possible.
The skeptics of singularity can also appeal to theory at the heart of the onion, where space-time behaves in a truly quantum way, such as the taking of overlays. There, nothing can be taken for granted. It becomes difficult to define the concept of zone, for example, it is therefore not clear what form the second law should take, and therefore the new theorems do not hold.
Bousso and physicists with similar views, however, suspect that a very quantum arena without a notion of zone is equivalent to a dead end for a light radius, and therefore that something Penrose would recognize as a singularity should persist in central theory and in our universe. The beginning of the cosmos and the heart of the black holes would really mark the edges of the map where the clocks cannot check and the space stops.
“Inside the black holes, I’m sure there is a notion of singularity,” said Netta EngelhardtMIT physicist who worked with Wall.
In this case, the fundamental theory still unknown of quantum gravity would not kill singularities but would demystify them. This truer theory would allow physicists to ask questions and calculate significant answers, but the language of these questions and answers would change considerably. Quantities in space-time such as position, curvature and duration can be useless to describe a singularity. Where time ends, other quantities or concepts may have to take their place. “If you were to make me guess,” said Penington, “whatever the quantum state describes the singularity itself does not have a notion of time.”
Original story reprinted with the permission of How many magazine,, an independent editorial publication of Simons Foundation whose mission is to improve the understanding of the public of science by covering the developments of research and the trends of mathematics and physical sciences and life.
