Non-equilibrium scalar two point functions in AdS/CFT

Abstract

In the first part of the paper, we discuss different versions of the AdS/CFT dictionary out of equilibrium. We show that the Skenderis-van Rees prescription and the "extrapolate" dictionary are equivalent at the level of "in-in" two point functions of free scalar fields in arbitrary asymptotically AdS spacetimes. In the second part of the paper, we calculate two point correlation functions in dynamical spacetimes using the "extrapolate" dictionary. These calculations are performed for conformally coupled scalar fields in examples of spacetimes undergoing gravitational collapse, the AdS 2 -Vaidya spacetime and the AdS 3 -Vaidya spacetime, which allow us to address the problem of thermalization following a quench in the boundary field theory. The computation of the correlators is formulated as an initial value problem in the bulk spacetime. Finally, we compare our results for AdS 3 -Vaidya to results in the previous literature obtained using the geodesic approximation and we find qualitative agreement.

Homogeneous isotropization and equilibration of a strongly coupled plasma with a critical point

“…Another perspective for future investigations consists in going beyond the calculation of one-point functions and study also higher order correlation functions [104][105][106][107][108] in far-from-equilibrium holographic settings. In particular, this kind of study may be of relevance for many different ongoing and future low energy heavy ion experiments, such as the BES program [109] being conducted at RHIC, the future fixed target (FXT) experiments [110,111] also at RHIC, the ongoing HADES experiment [112] at GSI, the future Compressed Baryonic Matter (CBM) experiment at FAIR/GSI [113,114], and also experiments in the future NICA facility [115].…”

From conformal blocks to path integrals in the Vaidya geometry

“…To illustrate the discussion in the introduction, we will compute the correlator G with t 1 < 0 < t 2 , using large-c CFT methods. The spatial Fourier transform of this correlator was computed via bulk methods in [26][27][28]. Since we study the correlator in the real space representation our results and their implications are new in the bulk, while our CFT calculations are entirely new.…”

Driven holographic CFTs

“…It would be interesting to develop these techniques further perhaps taking inspiration from the analytical models of [54,55]. This would allow us with a direct probe of fluctuations in the plasma, which can be contrasted with the dissipation in the system, the latter being measured by the entropy production through the growth of the horizon.…”