SCIENTIFIC EDUCATIONAL CENTER science idea

For the first time in history, scientists from the University of Manchester conducted direct experimental observations of the so-called Schwinger effect, an elusive effect that can occur only in the field of high-energy cosmic events, such as supernova explosions, collisions of neutron stars and black holes. By applying electric currents with a very high potential to specially designed graphene devices, scientists were able to obtain particle-antiparticle pairs from literally nothing, from a deep vacuum.

According to existing theories, a vacuum is a completely empty space in which there is no matter and even elementary particles. However, 70 years ago, Nobel laureate Julian Schwinger predicted that the strongest electric and magnetic fields could break the basis of the vacuum (space-time continuum), which would lead to the spontaneous appearance of particle-antiparticle pairs, the so-called Schwinger pairs.

Such an effect requires the participation of forces of truly cosmological scales — magnetic fields comparable in strength to the fields of magnetars, or electric potentials arising from collisions of high-energy compact space objects. The study of such processes and phenomena is one of the main directions in modern physics and the construction of new high-energy collider installations has already been planned for the implementation of such studies.

However, a research group from Manchester, led by another Nobel laureate, Professor Sir Andrew Geim, used graphene to produce positron-electron pairs using the Schwinger effect.

Scientists have made a number of devices from graphene, such as narrow junctions and superlattices, with the help of which the strongest electric fields were obtained within a fairly simple installation that fits on an ordinary desktop. And scientists were able to clearly observe the appearance of pairs of electrons and electron holes, which are a kind of solid-state analog of a positron. At the same time, all the characteristics of the particle and antiparticle production process were fully consistent with existing theoretical predictions.

In addition to the birth of Schwinger pairs, scientists were able to observe another unusual high-energy process, which does not yet have analogies either in elementary particle physics or in astrophysics. When scientists filled the vacuum area between the graphene layers with electrons and accelerated these electrons to a speed of 1/300 of the speed of light, these electrons suddenly became a kind of super-bright, their movement was able to provide a much larger electric current than allowed by the general rules of condensed matter quantum physics.

The explanation for this effect was the spontaneous appearance of additional charge carriers, electronic holes. And the theoretical description of this process is very different from the Schwinger theory applicable to vacuum.

It is still difficult to predict what consequences in physics, electronics and other related fields these achievements may lead to. But there is no doubt that all this can lead to the appearance of electronic devices based on quantum two-dimensional materials operating on completely new physical principles.

The article was published in the journal Science

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Source: dailytechinfo.org, sci-dig.ru