A magnetic monopole can exist not only as a mathematical abstraction.
Scientists have discovered traces of a magnetic monopole - a source of a magnetic field, the existence of which is denied by modern physics. The research results are published in the journal Science.
The electric and magnetic components of the electromagnetic field are described by similar equations, but behave differently. For example, an electric charge (electron) exists, but a magnetic one does not. That is, the electric field can be created by a single "pole" (monopole), and the magnetic field is created only by a pair of poles, north and south (dipole). Such a picture of the world is described by Maxwell's equations, which are basic for electromagnetism, and is confirmed by numerous experiments.
Despite this, there are several hypotheses that suggest that a magnetic monopole (an analog of an electron - an electric monopole) still exists. They are described only mathematically and are rather hypothetical assumptions; there is no real physical evidence of the existence of a magnetic monopole. Moreover, if it is still found, it will be necessary to rewrite Maxwell's equations and together with them the whole theory of electromagnetism.
The results of a recent study by American scientists have shown that a magnetic monopole can exist not only as a mathematical abstraction. For their experiments, they used quantum gas, in which, unlike ordinary gas, the particles are indistinguishable from each other. A typical quantum gas is electrons in the crystal lattice of a metal). Because of this property, the pressure and temperature of such a gas are described by the equations of quantum statistics, rather than ordinary molecular physics. Usually quantum gas is produced by cooling atoms to temperatures close to absolute zero. In this state, the atoms become practically immobile and it is convenient to study them.
The authors of the study exposed the quantum gas to radio and microwave irradiation. By changing the parameters of this radiation, scientists were able to change the internal magnetic characteristic of atoms - spin, which can be compared to the magnetic needle of a compass. Physicists sequentially changed the spin of almost motionless atoms between all possible values, that is, they forced it to make one "full revolution". However, at the end of the experiment, the spin did not return to its original state, but deviated slightly from it. Scientists explain this deviation precisely by the influence of a magnetic monopole. To rule out other possible interference, the scientists repeated the experiment, but this time eliminated the effect of the hypothetical monopole. In this case, the spin of the atoms returned to its original state without any distortion.