SciPost Phys. 8, 031 (2020) ·
published 28 February 2020
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We derive the low-energy theory of semi-quantized quantum Hall states, a recently observed class of gapless bilayer fractional quantum Hall states. Our theory shows these states to feature gapless quasiparticles of fractional charge coupled to an emergent Chern-Simons gauge field. These gapless quasiparticles can be understood as composites of electrons and Laughlin-like quasiparticles. We show that semi-quantized quantum Hall states exhibit perfect interlayer drag, host non-Fermi liquid physics, and serve as versatile parent states for fully gapped topological phases hosting anyonic excitations.
Henrik Schou Røising, Roni Ilan, Tobias Meng, Steven H. Simon, Felix Flicker
SciPost Phys. 6, 055 (2019) ·
published 8 May 2019
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We study Majorana fermions bound to vortex cores in a chiral $p$-wave
superconductor at temperatures non-negligible compared to the superconducting
gap. Thermal occupation of Caroli de Gennes-Matricon states, below the full
gap, causes the free energy difference between the two fermionic parity sectors
to decay algebraically with increasing temperature. The power law acquires an
additional factor of $T^{-1}$ for each bound state thermally excited. The
zero-temperature result is exponentially recovered well below the minigap
(lowest-lying CdGM level). Our results suggest that temperatures larger than
the minigap may not be disastrous for topological quantum computation. We
discuss the prospect of precision measurements of pinning forces on vortices as
a readout scheme for Majorana qubits.
