  We consider correlators for the flux of energy and charge in the background
of operators with large global $U(1)$ charge in conformal field theory (CFT).
It has recently been shown that the corresponding Euclidean correlators
generically admit a semiclassical description in terms of the effective field
theory (EFT) for a conformal superfluid. We adapt the semiclassical description
to Lorentzian observables and compute the leading large charge behavior of the
flux correlators in general $U(1)$ symmetric CFTs. We discuss the regime of
validity of the large charge EFT for these Lorentzian observables and the
subtleties in extending the EFT approach to subleading corrections. We also
consider the Wilson-Fisher fixed point in $d=4-\epsilon$ dimensions, which
offers a specific weakly coupled realization of the general setup, where the
subleading corrections can be systematically computed without relying on an
EFT.
