Rooted staggered fermions: good, bad or ugly?

نویسنده

  • Stephen R. Sharpe
چکیده

I give a status report on the validity of the so-called “fourth-root trick”, i.e. the procedure of representing the determinant for a single fermion by the fourth root of the staggered fermion determinant. This has been used by the MILC collaboration to create a large ensemble of lattices using which many quantities of physical interest have been and are being calculated. It is also used extensively in studies of QCD thermodynamics. The main question is whether the theory so defined has the correct continuum limit. There has been significant recent progress towards answering this question. After recalling the issue, and putting it into a broader context of results from statistical mechanics, I critically review the new work. I also address the related issue of the impact of treating valence and sea quarks differently in rooted simulations, discuss whether rooted simulations at finite temperature and density are subject to additional concerns, and briefly update results for quark masses using the MILC configurations. An answer to the question in the title is proposed in the summary.

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2 00 7 The author replies

I respond to the Bernard et al. comment on my letter “Chiral anomalies and rooted staggered fermions.” In their comment on my letter “Chiral anomalies and rooted staggered fermions,” [1] Bernard, Golterman, Shamir, and Sharpe [2] do not address the main point that the chiral symmetry group for the rooted theory has a higher rank than the target theory. This immediately calls into question wheth...

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تاریخ انتشار 2008