  We present a hydrodynamic theory for electron-hole magnetotransport in
graphene incorporating carrier-population imbalance, energy, and momentum
relaxation processes. We focus on the electric response and find that the
carrier and energy imbalance relaxation processes strongly modify the shear
viscosity, so that an effective viscosity can be negative in the vicinity of
charge neutrality. We predict an emergent eddy flow pattern of swirling
currents and explore its manifestation in nonlocal resistivity oscillations in
a strip of graphene driven by a source current.
