Is there any evidence of a magnetic monopole?

Question

(experimental or theoretical)

thanks for your answers.does anyone know about theoretical calculation of a magnetic monopole?

Answer 1

In physics, a magnetic monopole is a hypothetical particle that may be loosely described as "a magnet with only one pole" (see electromagnetic theory for more on magnetic poles). In more accurate terms, it would have net magnetic charge. Interest in the concept stems from particle theories, notably Grand Unified Theories and superstring theories that predict either the existence or the possibility of magnetic monopoles.

A number of attempts have been made to detect magnetic monopoles. One of the simplest is to use a loop of superconducting wire that can look for even tiny magnetic sources, a so-called "superconducting quantum interference detector", or SQUID. Given the predicted density, loops the size of a soup can would expect to see about one monopole event per year. Although there have been tantalizing events recorded, in particular the event recorded by Blas Cabrera on the night of February 14, 1982 (thus, sometimes referred to as the "Valentine's Day Monopole"), there has never been reproducible evidence for the existence of magnetic monopoles. The lack of such events places a limit on the number of monopoles of about 1 monopole per 1029 nucleons.

Other experiments rely on the strong coupling of monopoles with photons, as is the case for any electrically charged particle as well. In experiments involving photon exchange in particle accelerators, monopoles should be produced in reasonable numbers, and detected due to their effect on the scattering of the photons. The probability of a particle being created in such experiments is related to their mass -- heavier particles are less likely to be created -- so by examining such experiments limits on the mass can be calculated. The most recent such experiments suggest that monopoles with masses below 600 GeV/c² do not exist, while upper limits on their mass due to the existence of the universe (which would have collapsed by now if they were too heavy) is about 1017 GeV/c².

Non-inflationary Big Bang cosmology suggests that monopoles should be plentiful, and the failure to find magnetic monopoles is one of the main problems that led to the creation of cosmic inflation theory. In inflation, the visible universe was much smaller in the period before inflation, and despite the very short time before inflation, it would have been small enough for the whole visible universe to have been within the horizon, and thus not requiring many monopoles, perhaps only one. At the moment, versions of inflation seem to be the most likely cosmological theories.

Interestingly, the other major prediction of GUTs, proton decay, has also not been observed. The absence of these two key pieces of evidence has generally led to a decline in work on "classic" GUTs, and the introduction of more "radical" proposals, such as superstrings.

not yet

Answer 2

No Monopoles are an Invention for the purpose of explaining certain properties. If you take a bar magnet and break it in half, you will have two magnets, each with a north and south pole and it doesn't matter how small you make it, you cannot separate one pole from the other, Therefore there is no such thing as a Monopole. It would have a heck of a time trying to decide whether it would want to be a north pole or a south pole anyway.
There is no such thing as a brass magnet either, while we are on the subject.

Answer 3

hypothetical particle with a magnetic charge, a property analogous to an electric charge. As implied by its name, the magnetic monopole consists of a single pole, as opposed to the dipole, which is comprised of two magnetic poles. As yet there is no evidence for the existence of magnetic monopoles, but they are interesting theoretically. In 1931 the English physicist P.A.M. …

Answer 4

Nope...can't be done. If you cut a magnet in half, two poles always from. You can have particles that are negatively or positively charged...but that's not the same kind of thing.

Answer 5

experimentally and theorotically
there is only one rule

MAGNETIC MONOPOLE DOES NOT EXIST AT ALL

Answer 6

nope
http://en.wikipedia.org/wiki/Electromagnetic_theory

Answer 7

no