An Ellipse in a Crowd of Active Dumbbells
A crowd at the entrance to a narrow corridor behaves differently than in a spacious hall: some people get pressed against the walls, others are pushed forward. Roughly the same happens when an elongated particle finds itself in a fluid teeming with self-propelled dumbbells. Until now, it was unclear why such a particle moves faster along its long axis than across it, and how the crowd density affects its speed.