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Résumé |
Computing real-time Schwinger-Keldysh (SK) correlation functions away from
equilibrium stands out to be a theoretically outstanding as well as
phenomenologically relevant problem in the holographic approach to the strongly
interacting many-body systems. However, the realization of the bulk analogue of
the SK contour away from equilibrium has remained elusive within the holographic
framework for a long time. Lately, a promising (Horizon crosscap) prescription in
this context has been put forward by Crossley-Gloriosso-Liu, which however mostly
uses it in a static black hole background with slowly-varying probe dynamics. This
talk is based on an attempt to implement this prescription in a truly dynamical
geometry that is dual to a Bjorken flow in the boundary- a simple toy model
describing the expansion and cooling of the hadronic matter produced in the heavy-
ion collision. We will explicitly compute the SK correlations of the scalar
fluctuations of the Bjorken flow in a systematic late-time expansion, amenable to
a Borel resummation. In this context, I will also discuss our newly developed
matrix method which reproduces various known results and also gives an elegant way
of computing the SK correlation functions beyond equilibrium. Finally, I will
conclude with a set of open problems in this context. |
