Phase diagram of non-degenerate twisted mass fermions

Abstract

We determine the phase diagram and pion spectrum for Wilson and twisted-mass fermions in the presence of non-degeneracy between the up and down quark and discretization errors, using Wilson and twisted-mass chiral perturbation theory. We find that the CP-violating phase of the continuum theory (which occurs for sufficiently large non-degeneracy) is continuously connected to the Aoki-phase of the lattice theory with degenerate quarks. We show that discretization effects can, in some cases, push simulations with physical masses closer to either the CP-violating phase or another phase not present in the continuum, so that at sufficiently large lattice spacings physical-point simulations could lie in one of these phases.

arXiv comment27 pages, 17 figures. V2: minor stylistic and wording changes, matches published version

References in corpus (17)

• Chirally improving Wilson fermions - I. O(a) improvement
• Spontaneous Flavor and Parity Breaking with Wilson Fermions
• Up, down, strange and charm quark masses with Nf = 2+1+1 twisted mass lattice QCD
• Leading isospin breaking effects on the lattice
• Twisted-mass lattice QCD with mass non-degenerate quarks
• Chiral perturbation theory for the Wilson lattice action
• Twisted mass chiral perturbation theory at next-to-leading order
• The phase diagram of twisted mass lattice QCD
• Pion mass splitting and phase structure in Twisted Mass QCD
• QCD at θ\sim π
• On the phase structure of twisted mass lattice QCD
• Spontaneous violation of CP symmetry in the strong interactions
• Observations on discretization errors in twisted-mass lattice QCD
• Nucleon and Delta masses in twisted mass chiral perturbation theory
• Vacuum alignment and lattice artifacts: Wilson fermions
• Pion masses in 2-flavor QCD with $\eta$ condensation
• Twisted mass lattice QCD with non-degenerate quark masses

Cited by in corpus (5)

• Phase Diagram of Dynamical Twisted Mass Wilson Fermions at Finite Isospin Chemical Potential
• Impact of electromagnetism on phase structure for Wilson and twisted-mass fermions including isospin breaking
• Phase ambiguity of the measure for continuum Majorana fermions
• Dirac spectrum and chiral condensate for QCD at fixed $\theta$-angle
• Phase structure with nonzero ${\Theta }_{\mathrm{QCD}}$ and twisted mass fermions