the decay of charge currents, $l_{c,2}$ determines the effectiveness of current transfer from regions with high current density to regions with low current density. This latter mechanism is analogous to viscous momentum transfer. The flow profiles in dependence on $w$ can be separated into three regimes. For $w\gg l_{c,1}>l_{c,2}$, the samples are in the Ohmic regime, where the current is dissipated uniformly across the sample. The flow profile is flat. For $l_{c,1}<w<l_{c,2}$, the profile curvature is maximal, since on the one hand the current decay due to electron-electron scattering in the $m=1$ channel becomes inefficient, on the other hand the current transfer to the boundaries of the sample, where the flow is slowed down, is sufficiently strong. For even smaller widths $w<l_{c,2}$, the profile turns flat again, because the current transfer mechanism associated with $l_{c,2}$ ceases to be efficient. This characteristic pattern is shown in Fig. \[fig:Poiseuille\_slip\]. Current profiles are accessible experimentally, e.g. through the scanning single electron transistor technique of Refs. [@Ella2019; @Sulpizio2019].

Finally, we calculated the dispersions of the collective modes of a Dirac fluid. As do the transport coefficients, the collective modes separate into a sector of charge excitations and a sector of energy and imbalance excitations 