Speaker
Description
High-energy heavy-ion collisions generate an extremely strong magnetic field which plays a key role in a number of novel quantum phenomena in quark-gluon plasma (QGP), such as the chiral magnetic effect (CME). However, due to the complexity in theoretical modelings of the coupled electromagnetic fields and the QGP system, especially in the pre-equilibrium stages, the lifetime of the magnetic field in the QGP medium remains undetermined.
In this talk, we present a kinetic framework to study the dynamical decay of the magnetic field in the early stages of a weakly coupled QGP by solving the coupled Boltzmann and Maxwell equations. We find a universal separation of scales between the energy scale in the QGP medium and the strength of the magnetic field, irrespective of detailed interactions among quarks and gluons. The separation of scales allows for effective couplings between EM fields and the splittings among quarks and anti-quarks, which gives rise to the out-of-equilibrium induction effect. At late times, a magnetohydrodynamic description of the coupled system emerges. With respect to realistic collisions at RHIC and the LHC, we find that the residual strength of the magnetic field in the QGP satisfies a hierarchy relation: $m_q^2\ll |eB| \ll T^2$, when the system starts to evolve hydrodynamically. We also notice that the relative dominance from the electrical field and magnetic field can be reversed between RHIC and the LHC energies.
arXiv:2104.00831
