Critical points between quantum Hall states

Simple interacting field theories of quantum phase transitions between different Laughlin quantum Hall liquids are considered. In paper 1, the presence of a non-zero interaction strength at the critical fixed point is shown to lead to transport properties which depend sensitively on the order in which the measurement frequency and the absolute temperature are sent to zero; such results are of relevance to microwave conductivity measurements on quantum Hall systems (Engel et al. Physical Review Letters 71, 2638 (1993)). Paper 2 contains a description of perhaps the only solvable theory which accounts for the long-rage Coulomb interaction between the electrons.


  1. Non-zero temperature transport near fractional quantum Hall critical points, S. Sachdev, Physical Review B 57, 7157 (1998); cond-mat/9709243.
  2. Coulomb interactions at quantum Hall critical points of systems in a periodic potential, J. Ye and S. Sachdev, Physical Review Letters 80, 5409 (1998); cond-mat/9712161.