Pseudospin-1 wave scattering that defies chaos Q -spoiling and Klein tunneling

Q-spoiling is a known phenomenon in wave chaos, where an open chaotic cavity deformed from an integrable one exhibits a significantly reduced Q-value. In relativistic quantum mechanics, another mechanism that makes trapping of waves difficult is Klein tunneling. For chaotic scattering of a pseudospin-1 wave from a deformed scalar potential domain, both "leaking" mechanisms are thus present. Surprisingly, we find an energy range in which a pseudospin-1 chaotic cavity is capable of defying both Q-spoiling and super-Klein tunneling. The physical origin of this remarkable phenomenon is a peculiar type of unexpectedly robust edge modes that absolutely have no counterpart in nonrelativistic quantum or even in pseudospin-1/2 systems. The phenomenon can be tested experimentally in emerging electronic or photonic metamaterials with pseudospin-1 Dirac cones.