British scientists have discovered that light can “spontaneously generate” in the vicinity of large neutron stars and black holes due to quantum interactions between the vacuum and cosmic rays passing through it. Their findings were presented in the journal Physical Review Letters.
Today scientists believe that the vacuum, contrary to our common beliefs, is not the embodiment of absolute emptiness and just an empty space. It represents, in accordance with the laws of quantum physics, a constantly agitated "sea" of an infinite number of constantly born and self-destructing pairs of virtual particles and antiparticles. Their interaction, according to physicists, should have a special effect on the behavior of atoms and light.
For example, this quantum "sea" should have a special effect on the polarization of light in the presence of strong magnetic fields, causing it to split and polarize in the same way as light behaves in some crystals, causing it to split into two beams. Scientists have been talking about the existence of such an effect since the thirties of the last century, but they have not been able to record it until now.
Today, astronomers are trying to find traces of its existence by observing radio signals and other types of radiation emanating from pulsars, "dead stars" with an extremely powerful magnetic field.
Noble and his colleagues have discovered another curious manifestation of how a "sea" of non-existent particles that inhabit the void of vacuum can manifest itself in the real world, analyzing what happens to charged particles that pass through the vicinity of "dead stars".
Scientists drew attention to the fact that quantum fluctuations of the vacuum and powerful magnetic fields of pulsars will affect not only the behavior of light particles, but in a special way "slow down" the movement of various cosmic rays, accelerated to near-light speeds.
This process, Noble explains, will be very similar in essence to a curious effect discovered by Soviet physicists almost a hundred years ago. Back in 1934, Pavel Cherenkov and Sergei Vavilov noticed, while experimenting with gamma radiation, that when it gets into a liquid, it causes a weak but clearly noticeable glow in it due to the fact that gamma rays knock out electrons and accelerate them to speeds exceeding the speed of light in water.
For a long time, physicists did not believe that Cherenkov radiation can arise in a vacuum, since the speed of light in it cannot be exceeded. Calculations by British physicists show that this rule is violated when a cosmic ray or a beam of accelerated particles hits the vicinity of a pulsar or a light pulse from a super-powerful laser.
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In the latter case, as physicists note, it is necessary to build an extremely powerful laser capable of accelerating electrons to energies exceeding 1.3 teraelectronvolts, which so far only the most powerful colliders can do. Such light sources, Noble admits, will not be built even in the distant future.
For this reason, scientists propose to look for traces of the existence of this phenomenon in the vicinity of pulsars, whose magnetic fields are about five orders of magnitude stronger than those electric fields that generate the most powerful lasers in existence or under construction.
According to the authors of the article, virtually all high-energy gamma rays emanating from millisecond pulsars can be generated by similar quantum interactions between vacuum and high-energy cosmic rays.
Can this "spontaneous" light be found? According to Noble and his colleagues, astrophysicists may already have detected traces of its existence. The fact is that in 2009 the Fermi gamma-ray telescope showed that the center of the Milky Way produces an unusually large amount of gamma radiation, the brightness of which in the high-energy part of the spectrum significantly exceeded the theoretically predicted values.
Then scientists believed that decays of dark matter particles could have generated it, but later astronomers doubted this, having not found such an excess of radiation in the neighboring galaxy, the Andromeda Nebula. British physicists assume that it was generated not by this invisible substance, but by the phenomenon they discovered.
