Arvin Ash

How do Superconductors work at the Quantum level? (2021x9)

Udgivelsesdato: Apr 02, 2021

Thanks to Audible for sponsoring this video! Visit http://audible.com/arvinash , or TEXT "ArvinAsh" to 500-500 to start your FREE 30 day trial. Please Support this channel by downloading the free app at the link above. Maglev video on Lesics channel: https://www.youtube.com/watch?v=XjwF-STGtfE 0:00 Onnes discovers "magic" 2:51 Meissner effect 4:05 What causes resistance 6:09 BCS Theory 8:11 Cooper pairs 9:11 Bose-Einstein condensate 11:28 First room temp superconductor 11:53 Maglev trains 12:25 Audible special offer In 1908, Dutch physicist Heike Onnes figured out how to turn helium gas to liquified helium for the first time. He cooled Mercury and found that all its electrical resistance went away. Electricity in a superconducting wire will continue to flow virtually forever with no added energy. Superconductors also expel magnetic fields. So if you put a magnet over a superconductor, the magnet will levitate. How is this possible? Quantum mechanics can explain. In 1933 by Walther Meissner and Robert Ochsenfeld found that when a metal is cooled while in a small magnetic field, the flux is spontaneously excluded as the metal becomes superconducting. This is known now as the Meissner effect. Superconducting materials expel magnetic flux fields. Since magnetic fields cannot pass through it, a magnet over a superconductor magnet lifts up in order for the flux to flow to the opposite pole. This is what causes levitation. In 1957 John Bardeen, Leon Cooper and John Robert Schrieffer proposed what is now called the BCS theory. We need to first understand what causes resistance in the first place. Inside of a metal, the outermost electrons in the valence shell, being furthest away from the nucleus are so free to move around that a sample of metal can be treated as a bunch of atoms surrounded by a sea of electrons. But as electrons travel through the material, the atoms, which now have slightly positive charges because they have given up an electron