Strong magnetic fields can profoundly affect the equilibrium properties of strongly interacting matter, characterized by the equation of state and bulk thermodynamics. Although such fields are expected in off-central heavy-ion collisions, directly measuring their experimental imprints remains extremely challenging. To address this, we propose the baryon–electric charge correlations $\chi_{11}^{BQ}$ and the chemical potential ratio $\mu_Q/\mu_B$ as magnetic-field-sensitive probes, based on $(2+1)$-flavor lattice QCD simulations at physical pion masses. Along the transition line, $\chi_{11}^{BQ}$ and $(\mu_Q/\mu_B)_{\mathrm{LO}}$ in Pb–Pb collisions increase by factors of $2.1$ and $2.4$ at $eB \simeq 8M_\pi^2$, respectively.

We further extend this investigation to the QCD equation of state, examining leading-order thermodynamic coefficients for strangeness-neutral scenarios up to $eB \simeq 0.8$ GeV$^2$.

Relevant publications: PRD 112 (2025) 094508, PRD 111 (2025) 114522, PRL 132 (2024) 201903

Keywords: Lattice QCD, Heavy-ion collisions, QCD magnetometer, QCD equation of state