Gutzwiller-projected wave functions for the pseudogap state of underdoped high-temperature superconductors

Recent experiments strongly suggest that a Fermi-surface reconstruction and multiple Fermi pockets are important common features of the underdoped high-temperature cuprate superconductors. A related theoretical work [Phys. Rev. B 79, 134512 (2009)] has demonstrated that a number of hallmark phenomena observed in the underdoped cuprates appear naturally in the scenario of a paired electron pocket coexisting with unpaired hole pockets. We propose Gutzwiller-projected wave functions to describe this two-fluid state as well as two competing states in its vicinity. It is argued that a pseudogap state constructed from these wave functions may be selected by energetics at finite temperatures due to spin fluctuations.