quantum Hall effect
a quantum-mechanical version of the Hall effect
fractional quantum Hall effect
physical phenomenon in which the Hall conductance of 2D electrons shows precisely quantized plateaus at fractional values of e²/h
quantum spin Hall effect
a state of matter proposed to exist in special, two-dimensional, semiconductors that have a quantized spin-Hall conductance and a vanishing charge-Hall conductance
quantum anomalous Hall effect
effect in quantum mechanics where conductivity acquires quantized values