title: Localized many-particle Majorana modes with vanishing time-reversal symmetry breaking in double quantum dots.
abstract: We introduce the concept of spinful many-particle Majorana modes with local odd operator products, thereby preserving their local statistics. We consider a superconductor-double-quantum-dot system where these modes can arise with negligible Zeeman splitting when Coulomb interactions are present. We find a reverse Mott-insulator transition, where the even- and odd-parity bands become degenerate. Above this transition, Majorana operators move the system between the odd-parity ground state, associated with elastic cotunneling, and the even-parity ground state, associated with crossed Andreev reflection. These Majorana modes are described in terms of one, three, and five operator products. Parity conservation results in a 4π periodic supercurrent in the even state and no supercurrent in the odd state.
authors.affiliation: School of Mathematics and Physics, University of Queensland, Brisbane, 4072 Queensland, Australia.
authors.forename: Anthony R
authors.initials: AR
authors.lastname: Wright
authors.forename: Menno
authors.initials: M
authors.lastname: Veldhorst