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Register a new userComment on S. H. Simon, Interpretation of thermal conductance of the $ u=5/2$ edge, arXiv:1801.09687
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D. E. Feldman
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We address the interpretation proposed in [S. H. Simon, arXiv:1801.09687] of the thermal conductance data from [M. Banerjee et al., arXiv:1710.00492]. We show that the interpretation is inconsistent with experimental data and the sample structure. In particular, the paper misses the momentum mismatch between contra-propagating modes. Contrary to the claim of the paper, low energy tunneling involves a large momentum change. We consider only the small Majorana velocity mechanism [S. H. Simon, arXiv:1801.09687]. Other mechanisms, interpretations of the experiment, and their difficulties are beyond the scope of this Comment.
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Recent experiments [Banerjee et al, arXiv:1710.00492] have measured thermal conductance of the nu=5/2 edge in a GaAs electron gas and found it to be quantized as K approx 5/2 (in appropriate dimensionless units). This result is unexpected, as prior numerical work predicts that the nu=5/2 state should be the Anti-Pfaffian phase of matter, which should have quantized K=3/2. The purpose of this paper is to propose a possible solution to this conflict: if the Majorana edge mode of the Anti-Pfaffian does not thermally equilibrate with the other edge modes, then K=5/2 is expected. I briefly discuss a possible reason for this nonequilibration, and what should be examined further to determine if this is the case.
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