A hundred years ago next week, superconductivity was discovered. Now we know electric charge can flow through ultra-cold objects without resistance. How better to celebrate this anniversary than with an awesomely crazy idea about ultra-hot superconductors forming in deep space?
Physicists have a pretty good handle on how regular, low-temperature superconductors work. When certain materials are cooled to close to absolute zero, all the electrons condense, effectively forming a single entity through which charge can flow almost instantaneously. One of the big goals of modern science is to understand how higher-temperature superconductors work and perhaps one day create room-temperature superconductors, but French physicist Maxim Chernodub has a new theory that makes all those ideas look positively boring.
His idea is that superconductivity can suddenly arise in a vacuum with no materials present at all, as long as there is an incredibly strong magnetic field. The strength of the field and the temperature of the immediate area defy comprehension - Chernodub suggests this form of superconductivity would survive in temperatures of at least a billion degrees. For the sake of comparison, even the most massive stars don't reach temperatures much higher than 50,000 degrees.
Of course, we can't be talking about a pure vacuum, or there would be nothing around to carry the charge. Thankfully, the universe is definitely not a pure vacuum, and quantum mechanics tells us that it's full of virtual particles that momentarily pop in and out of existence.
Chernodub imagines a scenario in which an up quark and down antiquark pop into existence and form what's known as a rho meson. Under normal circumstances, this meson is too unstable to survive for long, but we're about as far away from normal circumstances as it gets. In the presence of a very strong magnetic field, the rho mesons would move along the lines of the field, which would lend it greatly added stability.
And here's where the superconductivity would kick in - the newly stable rho meson's spin would then interact with the field, lowering its effective mass to zero. This would create superconductivity and allow resistance-free movement for charge, all without any actual materials being present.
For any of this to work, there needs to be a phenomenally strong magnetic field, reaching strengths of about 10^16 tesla. For the sake of comparison, Earth's most powerful magnets can only reach about 30 T, and the most magnetized object in the known universe, a special type of neutron star known as a magnetar, still only reaches 10^10 T. So what could possibly form such a strong field?
As always seems to be the case, the answer is the Large Hadron Collider. Chernodub thinks a near collision between two lead ions - which, as they move, create magnetic fields - could, for one incredibly tiny fraction of a second, create a magnetic field of the required power, and this in turn would create an instant of vacuum superconductivity. So, as bizarre as this idea undoubtedly is, it's actually within the realm of experimental science, if only just barely.
Chernodub suspects vacuum superconductivity might have played a role in the early universe. In the primeval cosmos, he speculates that there were magnetic fields in excess of 10^16 T, and the periods of vacuum superconductivity were responsible for creating the mysterious large-scale magnetic fields that we now observe in the universe.
Via Physics World.
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