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Exact center symmetry and first-order phase transition in QCD with three degenerate dynamical quarks

G. Endrődi1, G. D. Moore2, A. Pieczynski3,4, and A. Sciarra5

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Phys. Rev. D 113, 114518 – Published 17 June, 2026

DOI: https://doi.org/10.1103/5rj7-xnq1

Abstract

We study QCD with three degenerate flavors of dynamical quarks using first-principles lattice simulations. For a specific choice of imaginary isospin chemical potential, this theory possesses an exact center symmetry, just like pure gauge theory. This exact symmetry is expected to be intact at low temperatures and spontaneously broken in the high-temperature regime. By analyzing the finite-size scaling of the Polyakov loop distribution, obtained with a dedicated multihistogram approach, we demonstrate that there is a first-order deconfinement phase transition in between. Our results are obtained employing stout-smeared rooted staggered quarks at one lattice spacing. Using simulations at different quark masses we sketch the behavior of QCD in the mass-isospin chemical potential plane, shedding new light on this corner of the fundamental phase diagram of the strong interactions.

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Phys. Rev. D 113, 114518– Published 17 June, 2026
  • Received 1 April 2026
  • Accepted 20 May 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.

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