Temperature dependent Fermi arcs in the normal state of the underdoped cuprate superconductors

Angle resolved photoemission experiments by Kanigel, et al (cond-mat/0605499) [Nature Physics 2, 447 (2006)] have made a remarkable observation that low energy electronic excitations in the normal state of underdoped cuprate superconductors exist on open ``Fermi arcs'' instead of a closed Fermi surface. These arcs shrink upon cooling, with the arc length appearing to extrapolate to nodal points at zero temperature. We show that this striking non-Fermi liquid behavior could result from the underdoped normal state above Tc lying in the vicinity of a quantum phase transition between a d-wave superconductor and a correlated insulating phase.