Interference (communication)

Quantum mechanics

Magnetic field

Phase (matter)

Quantum computer

Engineering

Majorana fermion

Andreev reflection

Telecommunications

Computer science

Physics

MAJORANA

Mathematics

Fermion

Topological insulator

Superconductivity

Condensed matter physics

Quantum

Combinatorics

Quantum Hall effect

Channel (broadcasting)

Electron

Topology (electrical circuits)

Electrical engineering

Nature Physics

The search for topological excitations such as Majorana fermions has spurred interest in the boundaries between distinct quantum states. Here, we explore an interface between two prototypical phases of electrons with conceptually different ground states: the integer quantum Hall insulator and the s-wave superconductor. We find clear signatures of hybridized electron and hole states similar to chiral Majorana fermions, which we refer to as chiral Andreev edge states (CAESs). These propagate along the interface in the direction determined by the magnetic field and their interference can turn an incoming electron into an outgoing electron or hole, depending on the phase accumulated by the CAESs along their path. Our results demonstrate that these excitations can propagate and interfere over a significant length, opening future possibilities for their coherent manipulation. The interface between a quantum Hall state and a superconductor hosts topological modes. Here, interference between two such modes turns an electron into either a hole or an electron depending on the phase difference along the interference path.

Interference of chiral Andreev edge states