Gapless pairing and the Fermi arc in the cuprates

We argue that the Fermi arc observed in angle-resolved photoemission measurements in underdoped cuprates can be understood as a consequence of inelastic scattering in a phase-disordered d -wave superconductor. We analyze this phenomenon in the context of strong-coupling Eliashberg theory, deriving a "single-lifetime" model for describing the temperature evolution of the spectral gap as measured by single-particle probes such as photoemission and tunneling.