  Quantum backflow is a counterintuitive effect in which the probability
density of a free particle moves in the direction opposite to the particle's
momentum. If the particle is electrically charged, then the effect can be
viewed as the contrast between the direction of electric current and that of
the momentum. To date, there has been no direct experimental observation of
quantum backflow. However, the effect has been simulated numerically (using
classical computers) and optically (using classical light). In this study, we
present the first simulation of quantum backflow using a real quantum computer.
