Physics of $\pi$-Meson Condensation and High Temperature Cuprate Superconductors

Abstract

The idea of condensation of the Goldstone $\pi$-meson field in nuclear matter had been put forward a long time ago. However, it was established that the normal nuclear density is too low, it is not sufficient to condensate $\pi$-mesons. This is why the $\pi$-condensation has never been observed. Recent experimental and theoretical studies of high temperature cuprate superconductors have revealed condensation of Goldstone magnons, the effect fully analogous to the $\pi$-condensation. The magnon condensation has been observed. It is clear now that quantum fluctuations play a crucial role in the condensation, in particular they drive a quantum phase transition that destroys the condensate at some density of fermions.

References in corpus (5)

• Electronic liquid crystal state in the high-temperature superconductor YBCO(6.45)
• Spin dynamics in the pseudogap state of a high-temperature superconductor
• In-plane anisotropy of spin excitations in the normal and superconducting states of underdoped YBa${}_2$Cu${}_3$O${}_{6+x}$
• Destruction of Neel order and local spin spirals in insulating La_{2-x}Sr_xCuO_4
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