Scientists Create One-Poled Magnet
TEHRAN (Tasnim) – If you break a compass needle in two, the resulting smaller magnets will have both north and south poles. Keep cutting the needle and each individual part will always have two poles - even down to the atomic level.
But the fact that this happens is a mystery, because scientists believe that a magnetic monopole - a magnet with just one pole - should exist to explain fundamental physics. While physical evidence is lacking, researchers have now engineered a synthetic monopole for the first time, allowing its mysterious properties to be explored, The Nation reported Saturday.
A magnetic monopole is a particle just like an electron, but with a magnetic rather than an electric charge. Around 80 years ago Paul Dirac, one of the founders of quantum physics, tried to imagine how this monopole could be consistent with the Standard Model.
He predicted that a magnetic monopole would leave a small whirlpool trail as it passed through an electron. Physical evidence of this behavior, however, has so far eluded scientist and so it was difficult to test the Dirac’s theory. Researchers at Amherst College in Massachusetts and Aalto University in Finland managed to simulate the behavior in an ultra-cold material that mimics a natural magnetic system.
To do this, scientists cooled rubidium atoms to a billionth of a degree above absolute zero. They used one rubidium atom to mimic an electron, and then created the magnetic field of a monopole by changing the alignment of millions of other rubidium atoms. Each of these atoms acts like a tiny compass needle pointing in a slightly different way. They then took pictures of the ‘electron’ as it interacted with the ‘magnetic field.’
As the synthetic monopole hit the electron, it created a vortex, just as Dirac predicted. While the new experiment, described in Nature, doesn’t prove that such monopoles exist outside the lab, it could help physicists know what to look for in nature. For instance, if such magnetic monopoles exist, they were likely formed just after the Big Bang when all of space was much hotter and denser than it is today.
“The creation of a synthetic magnetic monopole should provide us with unprecedented insight into aspects of the natural monopole,” said Professor David Hall from Amherst College.
“It’s not every day that you get to poke and prod the analogue of an elusive fundamental particle under highly controlled conditions in the laboratory,” he added. The discovery of a magnetic monopole in nature would provide a key piece of evidence to prove the Grand Unified Theory.
A Grand Unified Theory is the greatest goal of physics and would unify the four fundamental forces of nature; electromagnetism, the strong and weak nuclear forces and gravity. Currently, the theory of quantum mechanics, which encompasses the first three forces, seems to be incompatible with general relativity, which describes gravity.