Conductance quantization in topological Josephson trijunctions

Majorana zero modes are attracting a lot of attention as a new kind of emergent quasiparticles in condensed-matter physics. Here we propose a new and striking signature of the coupling between Majorana zero modes in a three-terminal Josephson junction made with topological superconductors. Recently three- and four-terminal junctions made either with conventional or with topological superconductors have been shown to exhibit Weyl crossings in their Andreev spectrum that lead to a nonzero quantized transconductance, like in the quantum Hall effect. In contrast with the other types of junctions, where the effect is limited to certain parameter regimes, we predict that, generically, any three-terminal Josephson junction made with topological superconductors is characterized by such a nonzero quantized transconductance. The quantization value is +2e(2)/h. Based on numerics, we check that this prediction is robust.

Automated summary

Majorana zero modes have attracted significant attention as emergent quasiparticles in condensed-matter physics. A new and striking signature of the coupling between Majorana zero modes in a three-terminal Josephson junction made with topological superconductors has been proposed. This coupling leads to a nonzero quantized transconductance, with a quantization value of +2e(2)/h, which is predicted to be a generic feature of such junctions made with topological superconductors.