Comment on "Lattice QCD constraints on the critical point from an improved precision equation of state"

Abstract

A recent Letter~\cite{Borsanyi:2025dyp} employs lattice QCD calculations of the equation of state, combined with entropy-density contour analysis, to place a lower bound of $\mu_B \gtrsim 450$~MeV on the location of the QCD critical endpoint (CEP). While the underlying lattice calculations represent an important advance in precision and systematic control, the method used to infer constraints on the CEP is not directly sensitive to critical behavior. In particular, the use of entropy contours does not directly probe the singular structure associated with the CEP, does not explicitly incorporate the relevant thermodynamic scaling fields, and relies on assumptions that are not strictly satisfied in finite systems. Consequently, the reported exclusion of a CEP below $\mu_B \approx 450$~MeV cannot be regarded as model-independent, as model-independent constraints require observables that are directly sensitive to the singular scaling behavior associated with critical phenomena.