In 1987 a Nobel Prize was awarded for the discovery of materials that could behave as superconductors at a temperature which is far above absolute zero. Typically, superconductivity only occurs when one cools a substance like Mercury down to around 3 degrees Kelvin with liquid Helium. I think that what happens looks a bit like this – the Mercury becomes one with the vibrations contained in empty space — the 2.7 degree Kelvin quantum vacuum.
As of 2019 the material with the highest accepted superconducting temperature is highly pressurized lanthanum decahydride (LaH10), whose transition temperature is 250 K (−23 °C) at elevated, 250 GPascal pressure.https://en.wikipedia.org/wiki/Room-temperature_superconductor
There is presently no good explanation for why we see superconducting behavior at high temperatures for certain materials. I didn’t enjoy the Wikipedia explanation in terms of Cooper pairs, so I decided to venture my own.
In superconducting materials, no electric field can exist. No charges or electrons can exist. EMF=0=IR. There is no resistance so there can be any current.
Room temperature superconductivity only happens because the extreme pressurization creates an artificially colder vacuum around the conductor.
“Colder?” You might ask. “I thought pressure made things warmer.” Tja. It makes air molecules move faster, but we aren’t talking about air molecules here, we’re talking about empty space – a substance with a temperature and energy density. Some call it the quantum vacuum. Some call it the noise floor of free-space. Some call it the cosmic microwave background radiation. I’ll just call it empty space.
It helps to think in terms of mirror images – something British people are particularly good at because of how they do everything backwards from the rest of the world. With matter and empty space as two sides of a looking glass, empty space looks cold to us, but we look cold to empty space. When we increase the pressure of empty space, it will feel hotter, but look colder to us and when the vacuum around an object gets colder, the object is going to behave colder and exhibit superconducting behavior. Essentially, the pressure creates a false vacuum around the conductor.
If this doesn’t connect intuitively, think of how coals glow red when you blow on them. Contrariwise, the hotter the fire, the stronger the draft, and a strong draft is colder than air that is still. When we put pressure on the fire, the coals glow red while the surrounding space becomes colder. It seems that pressure caused things in the coals to speed up while things in the surrounding space slowed down.
At this point you might remember: “Relativity tells us that things that move faster act like they are colder and spaced further apart because they have length contracted.”
Stepping away from the language of temperature and expressing the same concept in the equivalent language of motion, we see that when matter gets out of the way, current can flow quickly and intense pressure causes matter to move (vibrate) faster and concentrate (length contract) in small spaces within an object, causing the object to behave as a superconductor. An electrostatically equivalent explanation of length contraction can be given in terms of (figurative) spatial expansion, as in the 1937 superconductivity theory of Landau expansion. This is similar to how the universe only appears to expand, as when the space around an object sitting in sand acts like it expands when the sand begins to vibrate.
This explains the high temperature superconductivity of certain materials under high pressure, but it doesn’t explain cuprates – quasi-two-dimensional materials that demonstrate superconductivity at atmospheric pressure but at a temperature of 100 K — cold, but well above absolute zero.
What is quasi-two-dimensionality? Take a piece of paper and randomly poke holes in it until it is half holes and half paper. Make a stack of those papers and you have a quasi-two-dimensional substance.
How light or energy propagates through these objects simply cannot be described by mean field theory, no matter how creative you are with how you define the fields. They require something more like a real-space renormalization group method which predicts magnetic hot spots (monopoles) on each sheet with an extremely intense local field. These hot spots suck all of the charge out of the sheet, leaving behind the necessary conditions for superconductivity: no electric field can exist. No charges or electrons can exist. EMF=0=IR. There is no resistance so there can be any current.
Oftentimes problems become difficult to solve because they carry around a ton of theoretical baggage. When you reduce them to their base elements, they are eminently solvable.
When people ask for money while selling dreams of long distance transport of electricity using this principle, it is important to note that those magnetic hot spots (monopoles) tend to break the material down so that it can’t act as a superconductor forever. Likewise, dreams of flying cars with magnetic levitation due to eddy currents can be done with superconducting and normal conducting objects, it just requires a lot of energy to create those conditions. Mother nature doesn’t provide a free lunch when it comes to basic physics.
On the other hand, I might just be thinking to narrowly and lightning is an example of room-temperature superconductivity that happens when the voltage potential is high enough. Putting lightning in a bottle is another matter, though. They are trying to do that with fusion experiments and they’ve been making tiny pulses of lightning in a bottle in particle accelerators forever, but they consume far more power than they transport.
If I were to try to imagine a perfect, imaginary superconductor, I’d make it self-repairing. Magnetic monopoles would be born, they would reproduce themselves, and they would die in a semi-organic, negative entropy system. Negative entropy systems consume energy, though. We are negative entropy systems. Are we powered by room temperature superconductivity?
The image in the header was named Underwater Chernobyl. I’m not sure who owns the image.
Song: You’d be so nice to come home to