Vacuum fluctuations can cause the formation of virtual proto-universes, which, under certain conditions, are able to move from a virtual state to a real one.
Physicists have been trying for many years to build a quantum theory of gravity - so far, unfortunately, without success. Almost all of them agree that such a theory should combine Einstein's relativistic theory of gravitation with quantum mechanics, and this is a very, very difficult task.
Quantum mechanics, with all its paradoxes, nevertheless describes the properties of objects that exist in non-curved Newtonian space. The future theory of gravity should extend the probabilistic quantum-mechanical laws to the properties of space itself (more precisely, space-time), deformed in accordance with the equations of the general theory of relativity. How to do this using rigorous mathematical calculations, no one really knows yet.
Cold birth
However, the ways to such a union can be thought out at a qualitative level, and here very interesting prospects appear. One of them was considered by the famous cosmologist, professor at the University of Arizona Lawrence Krauss in his recently published book "A Universe From Nothing" ("Universe from nothing"). His hypothesis looks fantastic, but in no way contradicts the established laws of physics.
It is believed that our universe arose from a very hot initial state with a temperature of the order of 1032 kelvin. However, it is possible to imagine the cold birth of universes from a pure vacuum - more precisely, from its quantum fluctuations. It is well known that such fluctuations generate a great many virtual particles that literally emerged from nothing and subsequently disappeared without a trace. According to Krauss, vacuum fluctuations, in principle, are capable of giving rise to equally ephemeral proto-universes, which, under certain conditions, pass from a virtual state to a real one.
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Universe without energy
What is needed for this? The first and main condition is that the embryo of the future universe must have zero total energy. In this case, it is not only not doomed to almost instantaneous disappearance, but, on the contrary, can exist for an arbitrarily long time. This is due to the fact that, according to quantum mechanics, the product of the uncertainty in the energy of an object by the uncertainty in its lifetime should not be less than the final value - Planck's constant.
The separation of fundamental interactions in our early universe was in the nature of a phase transition. At very high temperatures, fundamental interactions were combined, but upon cooling below the critical temperature, separation did not occur (this can be compared to supercooling of water). At that moment, the energy of the scalar field associated with unification exceeded the temperature of the Universe, which endowed the field with negative pressure and caused cosmological inflation. The Universe began to expand very rapidly, and at the moment of symmetry breaking (at a temperature of about 1028 K) its dimensions increased by 1050 times. At this moment, the scalar field associated with the unification of interactions also disappeared, and its energy was transformed into a further expansion of the Universe.
As soon as the energy of an object is strictly equal to zero, it is known without any uncertainties, and therefore the time of its life can be infinitely long. It is due to this effect that two charged bodies located at very large distances are attracted or repelled from each other. They interact through the exchange of virtual photons, which, due to their zero mass, spread over any distance. On the contrary, gauge vector bosons carrying weak interactions, due to their large mass, exist for only about 10-25 seconds, as a result of which these interactions have a very small radius.
What kind of universe, albeit embryonic, with zero energy? As Professor Krauss explained to Popular Mechanics, there is nothing mystical about this: “The energy of such a universe is made up of positive energy of particles and radiation (and possibly also scalar vacuum fields) and negative potential energy of gravity. Their sum can be equal to zero - mathematics allows this. However, it is very important that such an energy balance is possible only in closed worlds, the space of which has a positive curvature. Flat and even more open universes do not possess such a property”.
The phase transition occurred in the evolution of the Universe three times: at a temperature of 10 to the 28 degree K (the Great Unification of interactions disintegrated), 10 to the 15 degree K (decay of the electroweak interaction) and 10 to the 12 degree K (quarks began to unite into hadrons).
Miracles of inflation
What happens if the quantum fluctuations of the vacuum give rise to a virtual universe with zero energy, which, due to quantum chances, has received some time for life and evolution? It depends on its composition. If the space of the universe is filled with matter and radiation, it will first expand, reach its maximum size and collapse in gravitational collapse, having existed for only a tiny fraction of a second. It is another matter if there are scalar fields in space that can trigger the process of inflationary expansion. There are scenarios in which this expansion not only prevents the gravitational collapse of the "bubble" universe, but also turns it into an almost flat and limitless world. Thus, the time of her life also grows immeasurably - almost to infinity. Thus,a tiny virtual universe becomes quite real - huge and long-lived. Even if its age is finite, it may well exceed the current age of our universe. Therefore, stars and star clusters, planets and even, what the hell is not joking, intelligent life can appear there. A full-fledged universe that arose literally out of nothing - these are the miracles that inflation is capable of!
Alexey Levin