Superconductivity Induced Topological Phase Transition at the Edge of Even Denominator Fractional Quantum Hall States

Understand

We show that every even-denominator fractional quantum Hall (FQH) state possesses at least two robust, topologically distinct gapless edge phases if charge conservation is broken at the boundary by coupling to a superconductor.

• The new edge phase allows for the possibility of a direct coupling between electrons and emergent neutral fermions of the FQH state.
• This can potentially be experimentally probed through geometric resonances in the tunneling density of states at the edge, providing a probe of fractionalized, yet electrically neutral, bulk quasiparticles.
• Other measurable consequences include a charge $e$ fractional Josephson effect, a charge $e/4q$ quasiparticle blocking effect in filling fraction $p/2q$ FQH states, and modified edge electron tunneling exponents.