Elementary particles in quantum field theory are described not as microscopic solid balls, not as matter, but as oscillations of quantum fields. Like any other physical system, the field strives to minimize its energy, get rid of unnecessary particles and "slide" into the most energetically favorable state. In theoretical physics, this state is usually called a vacuum. Contrary to its name, such a vacuum is not empty - in fact, virtual particle-antiparticle pairs are constantly being born and dying in it. However, the energy of such a "soup" of virtual particles is still less than the energy of a "soup" with an admixture of real particles.
For most of the fields described by the Standard Model, it is energetically favorable to slide into such a vacuum, zero state - graphically, such a potential looks like a hole, which is symmetric about an axis passing through the origin.
However, this is not the case for the Higgs field: its potential resembles a "Mexican hat" rather than a "hole", and a nonzero position becomes more advantageous. As a result, the entire space is permeated by a field of constant tension, which prevents the particles from accelerating and gives them mass - that is, the Higgs field. According to modern concepts, at high energies, the potential of the Higgs field bends downward to form a second pit, located below the pit in which we live. Although both pits are separated by a high potential barrier, the field can tunnel through it and collapse into a more favorable state, lying in the region of much higher energies (about 1012 teraelectronvolts). Therefore, our vacuum is considered "false", that is, it does not correspond to the present minimum of the Higgs field.
Dependence of the Higgs field potential on the considered energy scale.
As the theory predicts, in some cases, a spontaneous transition of the Universe from a false vacuum to a true one (the so-called "decay of a false vacuum") may occur, and huge energy will be released.
Usually this transition is described as the spontaneous formation of bubbles of the true vacuum in the false one. Under favorable conditions, these bubbles will expand infinitely, and under unfavorable conditions, they will collapse. It resembles the boiling of water, only instead of bubbles of steam we are dealing with a true vacuum. In particular, this is why some people are afraid of experiments at the LHC - they believe that these experiments could trigger a similar transition.
In reality, such fears are not very substantiated, since the energies attained at the collider are small - they are not enough for the appearance of true vacuum bubbles. In addition, with the parameters of the Standard Model known to us, the lifetime of the false vacuum exceeds the current age of the Universe, that is, within the framework of this model, our vacuum is metastable - that is, for us it does not differ from the true one.
Some theorists predict that in certain situations, the decay of the false vacuum may accelerate. For example, space-time around a black hole is strongly curved, and the rules for calculating the energy of a false vacuum are slightly changed, which should increase the likelihood of decay. Moreover, the smaller the black hole, the easier bubbles form around it and the greater the likelihood of decay. On the other hand, we still continue to live in a false vacuum, which indicates either the absence of such black holes, or flaws in our theories, or our incredible luck.
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