Application of the Maximum Entropy Method to the (2+1)d Four-Fermion Model

C. R. Allton; J. E. Clowser; S. J. Hands; J. B. Kogut; C. G. Strouthos

doi:10.1103/physrevd.66.094511

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Application of the Maximum Entropy Method to the (2+1)d Four-Fermion Model

C. R. Allton·J. E. Clowser·S. J. Hands·J. B. Kogut·C. G. Strouthos

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Abstract

We investigate spectral functions extracted using the Maximum Entropy Method from correlators measured in lattice simulations of the (2+1)-dimensional four-fermion model. This model is particularly interesting because it has both a chirally broken phase with a rich spectrum of mesonic bound states and a symmetric phase where there are only resonances. In the broken phase we study the elementary fermion, pion, sigma and massive pseudoscalar meson; our results confirm the Goldstone nature of the pi and permit an estimate of the meson binding energy. We have, however, seen no signal of sigma -> pi pi decay as the chiral limit is approached. In the symmetric phase we observe a resonance of non-zero width in qualitative agreement with analytic expectations; in addition the ultra-violet behaviour of the spectral functions is consistent with the large non-perturbative anomalous dimension for fermion composite operators expected in this model.

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C. R. Allton, J. E. Clowser, S. J. Hands, J. B. Kogut, C. G. Strouthos. 2002-08-19. Application of the Maximum Entropy Method to the (2+1)d Four-Fermion Model. https://doi.org/10.1103/physrevd.66.094511

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