Moments of the ARPES spectral function of an undoped Mott insulator

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We derive analytic expressions for the first three frequency moments of the single particle spectral function for one hole in a Mott insulator in terms of equilibrium spin correlation functions of the insulating state. We show that the ``remnant Fermi surface`` detected in ARPES experiments is, in fact, a reflection of the strong antiferromagnetic correlations of the system, not a reflection of the original band-structure Fermi surface. We suggest that ARPES data could be used to measure the magnetic specific heat.