Nature asymmetry

Electric charges and fields are magnetic, and only fields are magnetic. Can there be magnetic charges in the universe?

You can not make a single mistake and still lose. This is not a weakness - this is life.
- Jean-Luc Piccard

In science, and especially in physics, a fundamental number of physical processes are based on fundamental symmetries. In gravity, the force with which any mass acts on another is equal in magnitude and opposite in direction to the force exerted by another mass on the first.





The same is done for electric charges, although there is one catch: the electrical interaction can be positive or negative, in accordance with the signs of charges. In addition, electricity is closely associated with another interaction, magnetism.



Like electricity, there are positive and negative charges, where the similar repels the like, and the opposites attract, the magnetism has the north and south poles, which also have the same repelled, and different attracts. But magnetism demonstrates fundamental differences from electricity in a definite and obvious way:

• Electricity can have many charges, gathered together, or separate positive or negative charges.
• A magnetism can have many poles put together, but you cannot isolate the north pole from the south one.

In physics, two opposite charges or poles connected together are called a dipole, and one single charge is called a monopole.



With a gravitational monopole, everything is simple: it is mass. It is also simple with electric ones: any fundamental particle with a charge, such as an electron or a quark, will do.

But magnetic monopoles? As far as we know, they do not exist. The universe, where they exist, would be surprisingly different from ours. Think about how exactly electricity and magnetism are connected.



A moving electric charge, or electric current, creates a magnetic field perpendicular to the line of motion. A direct wire with an electric current flowing through it produces a magnetic field that goes in a circle around the wire. If you roll the conductor into a loop or coil, a magnetic field will appear inside it.

It turns out it works both ways. The laws of physics tend to symmetry. This means that if I have a loop or a coil of wire, and I change the magnetic field inside it, I will create an electric current that causes the electric charges to move. This is electromagnetic induction, discovered by Michael Faraday more than 150 years ago.



So, we have electric charges, electric current and electric field - but there are no magnetic charges or magnetic currents, only magnetic fields. You can change the magnetic field and force the electric charges to move, but you cannot force the magnetic charges to move, changing the electric field - since there are no magnetic charges.

In the same way, you can create a magnetic field by moving electric charges, but you cannot create an electric field by moving magnetic charges - again, they do not exist.

In other words, there is a fundamental asymmetry between the electrical and magnetic properties of our Universe. Therefore, the Maxwell equations for the fields E and B (electric and magnetic) are so very different.



The reason why the equations differ so much is that electrical charges (ρ and Q) and currents (J and I) exist, and their magnetic analogs do not. If you remove the electric charges and currents, they will become symmetrical up to fundamental constants.

But what if magnetic charges and currents existed? Physicists have been thinking about this for over a hundred years, and if they existed, we could write what Maxwell's equations would look like if magnetic monopoles were in nature. Here is what they would look like (in differential form)?



Again, up to fundamental constants, the equations now look very symmetrical! We could make magnetic charges move by simply changing the electric fields, create electric currents and induce electric fields. In the 1930s, Dirac was played with them, but then the generally accepted conclusion was that if they existed, they would have left behind some trace. This area was not taken seriously, since physics is essentially an experimental science; Without any evidence of the existence of magnetic monopoles, they are very difficult to justify.

But things began to change in the 1970s. People experimented with the Theories of Great Unification, or ideas about the fact that there can be much more symmetry in nature than we see. Symmetry can be broken, because of what in the Universe there are four different fundamental interactions, but perhaps all of them were combined on some kind of high energy into one? As a result, all these theories have a prediction of the existence of new high-energy particles, and in many cases, magnetic monopoles (in particular, the monopoly of 't Hooft-Polyakov ).



Magnetic monopoles have always been a tempting topic for physicists, and new theories have fueled this interest. So in the 1970s, the search for monopoles took place, and the most famous of them were the physicist Blas Cabrera [ grandson of the founder of physical research in Spain, Blas Felipe Cabrera / approx. trans. ]. He took a long wire, and twisted it into eight loops so that it could measure the magnetic flux going through it. If a monopole passed through it, then it would generate a signal with exactly eight magnetons . Well, if a standard magnetic dipole passed through it, it would generate a signal of +8 magnetons, immediately followed by a signal of -8 magnetons - thus these signals could be distinguished.


Blas Cabrera with her magnetic monopole detector

And so he built this device and waited. The device was not ideal, sometimes one of the loops sent a signal, and in even more rare cases, the signal was sent two loops simultaneously. But to detect a magnetic monopole, exactly eight were needed - but the device did not show more than two. The experiment went on unsuccessfully for several months, and as a result, they began to return to it only several times a day. On February 14, 1982, Blas did not come to his office because he was celebrating Valentine's Day. When he returned to work on February 15, he was surprised to find that the computer and the device on February 14 recorded a signal of exactly eight magnetons.



This discovery shook the public and generated a huge wave of interest. Larger devices with a larger surface area and a large number of loops were built, but, despite careful searches, no one else found a monopole. Steven Weinberg even wrote a poem to Blas Cabrera on February 14, 1983:

Roses are red,
Violets are blue,
It's time for monopole
Number TWO!

Roses are red,
Blue violets
Submit a second monopole
We would ask you!

[ Referring to the popular poem used in English-speaking countries in connection with the celebration of Valentine's Day // approx. trans. ]

But the second monopole did not appear. Was this the super rare glitch of the Cabrera experiment? Was this the only monopole in our part of the Universe that had accidentally passed through the detector? Since we have not yet found others, it is impossible to know for sure, but science must be replicable. But this experiment could not be reproduced.

Today, monopoles are still looking for experiments, but expectations are low.



Nature would be beautiful in its symmetry, but, as much as we would like, it is asymmetric, not at all levels. And no one is to blame; just the universe is what it is. It is better to accept it as such - no matter how aesthetically pleasing it would be otherwise - than to let our prejudices lead us away from the true path.