Two-flavor lattice QCD in the {epsilon} regime and chiral random matrix theory
- Theoretical Physics Laboratory, RIKEN, Wako 351-0198 (Japan)
- Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571 (Japan)
- Physics Department and Center for Theoretical Sciences, National Taiwan University, Taipei, 10617, Taiwan (China)
- High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801 (Japan)
- Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan)
The low-lying eigenvalue spectrum of the QCD Dirac operator in the {epsilon} regime is expected to match with that of chiral random matrix theory (ChRMT). We study this correspondence for the case including sea quarks by performing two-flavor QCD simulations on the lattice. Using the overlap fermion formulation, which preserves exact chiral symmetry at finite lattice spacings, we push the sea quark mass down to {approx}3 MeV on a 16{sup 3}x32 lattice at a lattice spacing a{approx_equal}0.11 fm. We compare the low-lying eigenvalue distributions and find a good agreement with the analytical predictions of ChRMT. By matching the lowest-lying eigenvalue we extract the chiral condensate, {sigma}{sup MS}(2 GeV)=(251{+-}7{+-}11 MeV){sup 3}, where errors represent statistical and higher order effects in the {epsilon} expansion. We also calculate the eigenvalue distributions on the lattices with heavier sea quarks at two lattice spacings. Although the {epsilon} expansion is not applied for those sea quarks, we find a reasonable agreement of the Dirac operator spectrum with ChRMT. The value of {sigma}, after extrapolating to the chiral limit, is consistent with the estimate in the {epsilon} regime.
- OSTI ID:
- 21027696
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 76, Issue 5; Other Information: DOI: 10.1103/PhysRevD.76.054503; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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