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We apply the recently developed extremely correlated Fermi liquid theory tothe Anderson impurity model, in the extreme correlation limit. We develop anexpansion in a parameter \lambda, related to n_d, the average occupation of thelocalized orbital, and find analytic expressions for the Green's functions toO(\lambda^2). These yield the impurity spectral function and also theself-energy \Sigma(\omega) in terms of the two self energies of the ECFLformalism. The imaginary parts of the latter, have roughly symmetric low energybehaviour (~ \omega^2), as predicted by Fermi Liquid theory. However, theinferred impurity self energy  \Sigma"(\omega) develops asymmetric corrections near n_d ~ 1, leading in turnto a strongly asymmetric impurity spectral function with a skew towards theoccupied states. Within this approximation the Friedel sum rule is satisfiedbut we overestimate the quasiparticle weight z relative to the known exactresults, resulting in an over broadening of the Kondo peak. Upon scaling thefrequency by the quasiparticle weight z, the spectrum is found to be inreasonable agreement with numerical renormalization group results over a widerange of densities.

Extremely Correlated Fermi Liquid study of the U=infinity Anderson Impurity Model