Superconductivity and Quantum Spin Disorder in Cuprates

Abstract
A fundamental connection between superconductivity and quantum spin fluctuations in underdoped cuprates is revealed. A variational calculation shows that Cooper pair hopping strongly reduces the local magnetization m0. This effect pertains to recent neutron scattering and muon spin rotation measurements in which m0 varies weakly with hole doping in the poorly conducting regime, but drops precipitously above the onset of superconductivity.