A Mesoscopic Resonating Valence Bond system on a triple dot

TL;DR

This paper proposes a mesoscopic triple-dot system that exhibits a resonating valence bond state, leading to a charge- and spin-dependent Josephson current, with potential implications for quantum devices.

Contribution

It introduces a novel triple-dot mesoscopic system that hosts a resonating valence bond state influencing Josephson effects in a superconducting setup.

Findings

Resonating singlet bonds induce a charge- and spin-dependent Josephson current.

The system demonstrates unique proximity effects in a SQUID geometry.

Potential applications in quantum information processing.

Abstract

We introduce a mesoscopic pendulum from a triple dot. The pendulum is fastened through a singly-occupied dot (spin qubit). Two other strongly capacitively islands form a double-dot charge qubit with one electron in excess oscillating between the two low-energy charge states (1,0) and (0,1); this embodies the weight of the pendulum. The triple dot is placed between two superconducting leads as shown in Fig. 1. Under well-defined conditions, the main proximity effect stems from the injection of resonating singlet (valence) bonds on the triple dot. This gives rise to a Josephson current that is charge- and spin-dependent. Consequences in a SQUID-geometry are carefully investigated.