Pseudogaps and quantum critically in underdoped cuprates

Abstract

We point out that, in a doped Mott insulator, the spin gap (pseudogap) phase can be stabilized by the proximity to an underlying quantum critical point associated with the quantum phase disordering of the superconducting order parameter. In the U(1) gauge theory formulation of the t-J model, the latter can be realized, from the d-wave superconducting state, through the quantum disorder phase transition of the slave boson. We introduce the slave boson-vortex duality formulation and show that the spin gap phase is stable at finite temperatures in the quantum critical and the quantum disordered regimes of the boson. We discuss the implications of this strong coupling theory in the context of the underdoped cuprates.