  We study the effective dynamics of an open scalar field interacting with a
strongly-coupled two-dimensional rotating CFT plasma. The effective theory is
determined by the real-time correlation functions of the thermal plasma. We
employ holographic Schwinger-Keldysh path integral techniques to compute the
effective theory. The quadratic effective theory computed using holography
leads to the linear Langevin dynamics with rotation. The noise and dissipation
terms in this equation get related by the fluctuation-dissipation relation in
presence of chemical potential due to angular momentum. We further compute
higher order terms in the effective theory of the open scalar field. At quartic
order, we explicitly compute the coefficient functions that appear in front of
various terms in the effective action in the limit when the background plasma
is slowly rotating. The higher order effective theory has a description in
terms of the non-linear Langevin equation with non-Gaussianity in the thermal
noise.
