  We investigate the possibility to generate quantum-correlated quasi-particles
utilizing analogue gravity systems. The quantumness of these correlations is a
key aspect of analogue gravity effects and their presence allows for a clear
separation between classical and quantum analogue gravity effects. However,
experiments in analogue systems, such as Bose-Einstein condensates, and shallow
water waves, are always conducted at non-ideal conditions, in particular, one
is dealing with dispersive media at nonzero temperatures. We analyze the
influence of the initial temperature on the entanglement generation in analogue
gravity phenomena. We lay out all the necessary steps to calculate the
entanglement generated between quasi-particle modes and we analytically derive
an upper bound on the maximal temperature at which given modes can still be
entangled. We further investigate a mechanism to enhance the quantum
correlations. As a particular example we analyze the robustness of the
entanglement creation against thermal noise in a sudden quench of an ideally
homogeneous Bose-Einstein condensate, taking into account the super-sonic
dispersion relations.
