Fractional Josephson effect in number-conserving systems

Meng Cheng; Roman Lutchyn

doi:10.1103/PhysRevB.92.134516

← Back to search

Fractional Josephson effect in number-conserving systems

Meng Cheng, Roman Lutchyn

DOI 10.1103/PhysRevB.92.134516 · Physical Review B

T1

Active bibliographic source — not scientific approval

Bibliographic access preserves source history; it does not approve extracted materials or validate reported claims. Review warnings on each occurrence separately.

Abstract

We study the fractional Josephson effect in a particle-number-conserving system consisting of a quasi-one-dimensional superconductor coupled to a nanowire or an edge carrying e/m fractional charge excitations with m being an odd integer. We show that, due to the topological ground-state degeneracy in the system, the periodicity of the supercurrent on magnetic flux through the superconducting loop is nontrivial, which provides a possibility to detect topological phases of matter by the dc supercurrent measurement. Using a microscopic model for the nanowire and quasi-one-dimensional superconductor, we derived an effective low-energy theory for the system which takes into account effects of quantum phase fluctuations. We discuss the stability of the fractional Josephson effect with respect to the quantum phase slips in a mesoscopic superconducting ring with a finite charging energy.