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More than a century after its discovery, superconductivity remains one of the strangest and most transformative phenomena in science. From quantum computers and fusion reactors to the ongoing search for room-temperature superconductors, researchers are still uncovering the physics behind a quantum state that seems to defy the normal rules of matter.
In 1911, a Dutch physicist with an impressively Edwardian moustache decided to see what would happen if he cooled a thread of mercury to close to absolute zero. Just a few years earlier, the same physicist, Heike Kamerlingh Onnes, had been the first to liquify helium and it was with this super cold liquid gas he set to work. He had expected the mercury’s electrical resistance to decrease steadily as it became colder – after all, as heat drains from matter, atomic vibrations slow and this allows electrons to pass more easily. He had also expected the resistance to eventually level off, but as the mercury hit a temperature of four Kelvin, something strange happened and, instead of plateauing, the resistance collapsed abruptly to zero. The current flowed through the wire without losing energy as heat. It wasn’t simply becoming a better conductor with less resistance. The resistance had vanished entirely, allowing the electricity to circulate without measurable friction or decay. The mercury was no longer just a conductor of electricity; it had become a superconductor [1]. Read the rest at Philosophical Magazine Comments are closed.
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