Have quantum scars been observed?

Abstract

Wilkinsonet al.1 have reported observations of oscillations in the current of a resonant tunnelling diode in a magnetic field. They proposed that this provides the first direct experimental evidence for quantum ‘scarring’ in a real chaotic system. But we believe that Wilkinson et al. have not observed quantum scars in the usual sense. They considered a far-from semiclassical regime where current theories of scarring are not valid. Demonstrating these effects in a solid-state device is a tremendous achievement. However, we believe that even in the semiclassical limit this type of experiment does not go beyond other experiments on atoms in magnetic fields as a probe of scarring.