As explained through How do Superconductors work at the Quantum level, superconductors
exhibit remarkable properties such as zero electrical resistance and magnetic field expulsion. At
the quantum level, ordinary conductors resist because electrons scatter off vibrating atoms,
losing energy. However, in superconductors, electrons form Cooper pairs due to interactions with
lattice vibrations, or phonons. These pairs act as bosons, energy-carrying subatomic particles, not
fermions, enabling them to occupy the same quantum state and move in a coherent wave-like
manner without scattering. This collective behavior prevents energy loss, allowing electricity to
flow perfectly. The BCS theory, proposed in 1957, describes this mechanism, showing how low
temperatures reduce lattice vibrations, allowing Cooper pairs to remain stable. Additionally,
superconductors expel magnetic fields through the Meissner effect, which is linked to the
quantum properties of the electron pairs. Thus, superconductivity is a macroscopic quantum
phenomenon arising from the intricate interplay between electrons and the atomic lattice.
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In The Fastest train ever built | The complete physics behind it, the narrator explains how
Superconductors lie at the heart of the revolutionary SC Maglev train, leveraging quantum
mechanics to achieve unparalleled efficiency and speed. At the quantum level, superconductivity
enables materials to conduct electricity with zero resistance when cooled below their critical
temperature. In the SC Maglev, superconducting magnets use this phenomenon to produce
continuous, powerful DC currents without energy loss, a feat impossible with conventional
electromagnets. This zero-resistance state is achieved by cooling niobium-titanium alloy
conductors to 4.5 Kelvin using liquid helium, ensuring uninterrupted current flow for levitation,
propulsion, and guidance.
Levitation occurs through figure-eight-shaped coils along the guideway, where the motion of the
superconducting magnets induces currents that generate opposing magnetic forces. This offsets
gravity and stabilizes the train at speeds over 600 km/h. Quantum mechanics further governs the
guidance system by utilizing the interplay of induced currents in adjacent coils, dynamically
centering the train without physical contact. The reliance on cryogenics to maintain the
superconducting state highlights the sophistication of integrating quantum principles into
practical applications. The video illustrates how the SC Maglev transforms the complex physics
of superconductivity into real-world marvels, offering insights into the boundless potential of
quantum-level engineering.