Explaining the strange spin dependence of the "tunneling anomaly" in compressible quantum Hall bilayers

June 29, 2018

In a recently-published series of papers, I explored the problem of the "tunneling anomaly" in bilayers of composite Fermions, together with Debanjan Chowdhury and Patrick Lee.  Our goal was to explain a recent series of experiments by Jim Eisenstein et. al. at Caltech, which observed a vanishing of the tunneling amplitude between two copies of the half-filled Landau level at low bias voltage. The dependence of this amplitude on the spin polarization of the composite fermion systems was especially unusual, and in direct contradiction to previous theories.

We ultimately found a plausible explanation for this phenomenon, which can be understood using the language of hydrodynamic spreading of electron charge. Our results are written up in a series of papers in Physical Review Letters and Physics Review B: