Electromagnetic fields and anomalous transports in heavy-ion collisions—a pedagogical review

Abstract

The hot and dense matter generated in heavy-ion collisions may contain domains which are not invariant under P and CP transformations. Moreover, heavy-ion collisions can generate extremely strong magnetic fields as well as electric fields. The interplay between the electromagnetic field and triangle anomaly leads to a number of macroscopic quantum phenomena in these P-and CP-odd domains known as the anomalous transports. The purpose of the article is to give a pedagogical review of various properties of the electromagnetic fields, the anomalous transports phenomena, and their experimental signatures in heavyion collisions. CONTENTS

Covariant chiral kinetic equation in the Wigner function approach

“…In magnetic fields, the chiral anomaly will lead to an electric current along the magnetic field resulting from an imbalance of chirality, which is called the chiral magnetic effect (CME) [3][4][5][6], for reviews, see, e.g., Ref. [6][7][8][9]. This effect gives another example of AVV coupling among the vector current, the chiral chemical potential of fermions and the magnetic field.…”

Event-by-event generation of vorticity in heavy-ion collisions

“…Relativistic heavy-ion collisions provide us with the environments in which we can study the strongly interacting matter under unusual conditions, like extremely high temperature [1] and extremely strong magnetic field [2,3]. Recently, it was realized that noncentral heavy-ion collisions can also generate finite flow voriticty and thus provide us with a chance to study quark-gluon matter under local rotation [4,5,6,7].…”

Phenomenology of anomalous chiral transports in heavy-ion collisions

“…In Fig. 1 (right), we present the numerical result for the magnetic fields as well as the electric fields at t = 0 (defined as the time when the two nuclei overlap maximally) and at ⃗ r = ⃗ 0 (the center of the overlapping zone) [2,20]. The simulations show some interesting features of the electromagnetic fields in heavy-ion collisions.…”

“…Gauss, and for LHC Pb + Pb collisions at √ s = 2.76 TeV the magnetic field can reach the order of 10 20 Gauss. More realistic numerical simulations indeed confirm that the high-energy heavy-ion collisions can generate extremely strong magnetic fields as well electric fields.…”