AdS4CME

Science background:

The Chiral Magnetic Effect (CME) is an exotic transport phenomenon leading to a separation of charges in the quark gluon plasma produced in heavy ion collision at the relativistic heavy ion collider RHIC in Brookhaven (USA) and at the large hadron collider LHC in Geneva (Switzerland). Its deep theoretical origin is rooted in the one of the most fundamental properties of quantum field theories: the chiral anomaly. Due to the anomaly particles can change their chirality in a non-trivial gauge field background, such as parallel electric and magnetic fields. The anomaly also gives rise to the generation of an electric current along a magnetic field if a chiral imbalance is present. 

In heavy ion collisions the origin of the chiral imbalance can be attributed to the topologically non-trivial fluctuations in the gluon fields. The conditions under which this can happen are exact analogous of the famous Sakharov conditions for baryogenesis: symmetry breaking, C- and CP-violation and far-from-equilibrium physics.  The CME can therefore be seen as an experimentally testable analogue of the mechanisms responsible for the matter/anti-matter asymmetry in the universe. 

An additional ingredient in heavy ion collisions is the fact that the quark gluon plasma is in a strongly quantum correlated state. A key signature of this strong coupling nature is the fact that it is the most perfect liquid in the universe. However, it makes the theoretical treatment very difficult. The gauge/gravity or holographic duality has bee suggested very early on as a theoretical tool to describe this strongly coupled quantum state. The gauge/gravity duality has its origins in string theory and postulates that string theory or more generally gravity with asymptotic Anti de-Sitter boundary conditions is dual to a strongly coupled quantum field theory living on the boundary of the AdS space-time. There have been numerous applications of the gauge/gravity duality to the physics of the quark gluon plasma, most emblematically predicting a very small lower bound for the viscosity and thus explaining the almost perfect fluid property. 

Mission statement:

The AdS4CME collaboration uses the holographic duality to develop models that can address some of the key features relevant for the CME in heavy ion collisions and thus contribute to a deeper theoretical understanding of this fascinating field of fundamental physics.

​