Equation 7 · From Origins to Frontier: A History of Quantum and Condensed-Matter Systems
What does this equation mean?
Read the formula alongside the article passage below. Each part has a deeper page with its role in the equation, the supporting passage and nearby citations.
the transition temperature. Read the equation part by part below; each part has a contextual explanation and a link to its mathematical background.
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subscript
The lower label selects a particular version, component, or indexed member of the quantity. For example, x₀ and xₜ can be values at different positions.
How to interpret it
Read this expression with the definitions, units, and assumptions supplied by the article.
What the article says around this equation
The exponential is the important feature, not decoration: it says depends on the coupling strength in a way that is extraordinarily sensitive at weak coupling and saturates at strong coupling, and it predicts that heavier isotopes of the same element (which lower ) should lower in a specific, measurable way — the isotope effect, observed before BCS existed and one of the clues that pointed toward a phonon mechanism in the first place. The formula also predicts an upper ceiling: no phonon-mediated superconductor should exceed roughly 30–40 kelvin, because for any real lattice is bounded. That ceiling is exactly what shattered in 1986.
Sources cited in the article section
- [2] Theory of Superconductivity ↗
- [3] July 1957: Bardeen, Cooper, and Schrieffer submit their paper, 'Theory of Superconductivity' ↗
These citations give research context. Read each source to check which claims it supports.
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