Effect of low-lying fermion modes in the $\epsilon$-regime of QCD

Abstract

We investigate the effects of low-lying fermion eigenmodes on the QCD partition function in the $\epsilon$-regime. The fermion determinant is approximated by a truncated product of low-lying eigenvalues of the overlap-Dirac operator. With two flavors of dynamical quarks, we observe that the lattice results for the lowest eigenvalue distribution, eigenvalue sum rules and partition function reproduce the analytic predictions made by Leutwyler and Smilga, which strongly depend on the topological charge of the background gauge configuration. The value of chiral condensate extracted from these measurements are consistent with each other. For one dynamical quark flavor, on the other hand, we find an apparent disagreement among different determinations of the chiral condensate, which may suggest the failure of the $\epsilon$-expansion in the absence of massless Nambu-Goldstone boson.

arXiv comment23 pages, 9 figures

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Cited by in corpus (13)

• Continuum Limit Physics from 2+1 Flavor Domain Wall QCD
• Evidence of effective axial U(1) symmetry restoration at high temperature QCD
• Two-flavor lattice QCD in the epsilon-regime and chiral Random Matrix Theory
• Lattice study of meson correlators in the epsilon-regime of two-flavor QCD
• Overlap Hypercube Fermions in QCD Simulations Near the Chiral Limit
• Finite Volume Scaling of Pseudo Nambu-Goldstone Bosons in QCD
• Spontaneous chiral symmetry breaking in QCD:a finite-size scaling study on the lattice
• Exploring Topology Conserving Gauge Actions for Lattice QCD
• Partially quenched chiral perturbation theory in the epsilon-regime
• Finite-size scaling for the left-current correlator with non-degenerate quark masses
• Determining F_pi from spectral sum rules
• Probing the chiral weak Hamiltonian at finite volumes
• Overlap Hypercube Fermions in QCD