Electron Spectral Function and Algebraic Spin Liquid for the Normal State of Underdoped HighTcSuperconductors

We propose to describe the spin fluctuations in the normal state (spin-pseudogap phase) of underdoped high $T_c$ cuprates as a manifestation of an algebraic spin liquid. Within the slave boson implementation of spin-charge separation, the normal state is described by massless Dirac fermions, charged bosons, and a gauge field. The gauge interaction, as an exact marginal perturbation, drives the mean-field free-spinon fixed point to a new spin-quantum fixed point—the algebraic spin liquid. Luttinger-liquid-like line shapes for the electron spectral function are obtained in the normal state, and we show how a coherent quasiparticle peak appears as spin and charge recombine.