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Tensor renormalization group study of cold and dense QCD in the strong coupling limit

Yuto Sugimoto1,*, Shinichiro Akiyama2,3,†, and Yoshinobu Kuramashi2,‡

  • *Contact author: sugimoto@nucl.phys.tohoku.ac.jp
  • †Contact author: akiyama@ccs.tsukuba.ac.jp
  • ‡Contact author: kuramasi@het.ph.tsukuba.ac.jp
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Phys. Rev. D 113, 114509 – Published 11 June, 2026

DOI: https://doi.org/10.1103/v5v2-7mq5

Abstract

We study the phase structure of the (3+1)-dimensional cold and dense QCD with the Kogut–Susskind quark in the strong coupling limit using the tensor renormalization group method. The chiral and nuclear transitions are investigated by calculating the chiral condensate and the quark number density as a function of the chemical potential. For a fixed temporal extent Nτ=8, we determine the critical quark masses mcχ and mcn for the chiral condensate and the quark number density, respectively, at which the first-order phase transition terminates with the vanishing discontinuity in thermodynamic quantities. We find that both quantities at the same quark mass exhibit a discontinuity at the same chemical potential, and the resulting critical quark masses are consistent with each other. We also compare our results for the critical quark masses with those obtained from the Monte Carlo simulation in the dual formulation and from the mean-field analysis. We further confirm the first-order phase transition at finite quark mass on a 10244 lattice, which is essentially in the thermodynamic limit at zero temperature, as expected from the mean-field analysis.

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Phys. Rev. D 113, 114509– Published 11 June, 2026
  • Received 29 January 2026
  • Accepted 8 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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