Quantum Matter Seminar

We show that a fractional quantum Hall edge can coherently convert fractional charge into a neutral Majorana excitation at an interface with a chiral non-Abelian spin liquid. For a Laughlin state at $\nu=1/m$, this conversion is topologically allowed only when $m=p^2$: the charge-$e/p$ edge fermion can couple to the counter-propagating Majorana mode of the spin liquid. As a result, one Majorana component of the charge-$e/p$ fermion is gapped, while the remaining one propagates at the edge. For one-component electronic Laughlin states, the Ising spin field is confined, and the interface realizes the spin-Ising edge theory. For general FQH states, the full Ising sector survives when the residual Abelian condensate has even order. We propose conductance, shot-noise, and interferometric signatures that electrically identify these interfaces, even though they support only neutral modes.