Review of the mechanisms for integer quantum Hall breakdown

Sammanfattning

This literature study provides a review of two different theoretical frameworks advanced to explain the observed breakdown of topological protection in the integer quantum Hall effect embedded in an ultra-strong coupled cavity. The first mechanism attributes the backscattering to non-local, vacuum-mediated electron hopping driven by the anti-resonant terms of the light-matter coupling Hamiltonian. The second framework proposes a purely classical electrostatic explanation in which backscattering is facilitated by counter-propagating single-edge electron channels formed from image charges in the cavity resonator. This review evaluates the simplifications, theoretical bounds and empirical advantages of both models with respect to both complementary split-ring resonator cavity regime transport data and to related architectures. Other possible synergistic effects are proposed to bridge the gap between the two frameworks and finally, it is concluded that replicating magnetotransport measurements in non-metallic resonator cavities should be conducted to decouple cavity-mediated and electrostatic effects.