After wrapping up special and general relativity, Albert Einstein tried, and failed, to devise a theory of superconductivity. Werner Heisenberg, the physicist who came up with the Heisenberg uncertainty principle, struggled with the problem, as did other pioneers of quantum mechanics like Niels Bohr and Wolfgang Pauli. Felix Bloch, another thwarted theorist, jokingly concluded: Every theory of superconductivity can be disproved.
You seldom hear in any of Einstein biography of him dabbling in trying to solve this.
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