Speaker
Description
QCD equation of state (EoS) characterizes the equilibrium properties of strongly interacting hot and dense matter. External factors, especially strong magnetic fields reaching magnitudes comparable to the QCD scale, can significantly influence this characterization. Of particular interest is how such strong magnetic fields affect the changes in degrees of freedom and thermodynamic properties near the QCD transition. To this end, we have carried out lattice simulations of $(2+1)$-flavor QCD using highly improved staggered quarks at the physical pion mass on $32^3 \times 8$ and $48^3 \times 12$ lattices. With magnetic field strength ($eB$) ranging up to $45 m_{\pi}^2 \sim 0.8~{\rm GeV}^2$ and temperature ($T$) window focussed around $T_{pc}$, we observe intriguing non-monotonic behaviours in the $T$-$eB$ dependence of pressure and number density, which are absent at vanishing magnetic fields. We will also discuss how the HRG model and the magnetized ideal gas serve as references for low-$T$, weak-$eB$ and high-$T$, strong-$eB$ regimes, respectively. Furthermore, we present results for higher-order thermodynamic observables, energy and entropy density, highlighting the significant impact of magnetic fields.
