  Baryon number density perturbations offer a possible route to experimentally
measure baryon number susceptibilities and heat conductivity of the quark gluon
plasma. We study the fluid dynamical evolution of local and event-by-event
fluctuations of baryon number density, flow velocity and energy density on top
of a (generalized) Bjorken expansion. To that end we use a
background-fluctuation splitting and a Bessel-Fourier decomposition for the
fluctuating part of the fluid dynamical fields with respect to the azimuthal
angle, the radius in the transverse plane and rapidity. We examine how the time
evolution of linear perturbations depends on the equation of state as well as
on shear viscosity, bulk viscosity and heat conductivity for modes with
different azimuthal, radial and rapidity wave numbers. Finally we discuss how
this information is accessible to experiments in terms of the transverse and
rapidity dependence of correlation functions for baryonic particles in high
energy nuclear collisions.
