Speaker
Description
Strong magnetic fields, attaining magnitudes comparable to the QCD scale, can significantly affect the equilibrium properties and bulk thermodynamics of strongly interacting matter. While such strong fields are expected in off-central heavy-ion collisions, directly measuring their imprints, such as chiral magnetic effects, remains challenging.
In this talk, we propose the baryon-electric charge correlations $\chi^{\rm BQ}_{11}$ and the chemical potential ratio $\mu_{\rm Q}/\mu_{\rm B}$ as effective probes for magnetic fields in heavy-ion collisions [1, 2]. This is based on our (2+1)-flavor QCD lattice simulations at physical pion masses, focusing on the pseudocritical temperature regime. To bridge theoretical predictions with experiment, we construct proxy observables and implement systematic kinematic cuts within the hadron resonance gas (HRG) framework to emulate detector acceptances of the STAR and ALICE experiments.
Extending our investigation into the QCD equation of state (EoS), we examine the behavior of bulk thermodynamic expansion coefficients under extremely strong magnetic fields [3]. Our current $eB$ window spans up to $0.8~{\rm GeV}^2 \sim 45 m_{\pi}^2$, revealing intriguing non-monotonic behaviors in the $T$-$eB$ dependence of pressure and number density, which are absent at vanishing and relatively weak magnetic fields. The HRG model and the magnetized ideal gas serve as useful references for the low-$T$, weak-$eB$ and high-$T$, strong-$eB$ regimes, respectively. Furthermore, we also discuss higher-order thermodynamic observables, energy and entropy density, highlighting the significant impact of magnetic fields.
[1] Heng-Tong Ding, Jin-Biao Gu, Arpith Kumar, Sheng-Tai Li, Jun-Hong Liu, Phys. Rev. Lett. 132, 201903 (2024)
[2] Heng-Tong Ding, Jin-Biao Gu, Arpith Kumar, Sheng-Tai Li, arXiv:2503.18467 [hep-lat]
[3] Heng-Tong Ding, Jin-Biao Gu, Arpith Kumar, Sheng-Tai Li, PoS LATTICE2024 (2025) 175, and work in progress
