Parity measurement of one- and two-electron double well systems

TL;DR

This paper proposes a measurement scheme using single-electron transistors to determine the parity and spin states of electrons in double well systems, enabling non-localized basis measurements in solid-state qubits.

Contribution

It introduces a novel measurement approach for single and two-electron double well systems using SETs, capable of projective measurements in parity and spin bases.

Findings

The scheme can measure parity eigenstates with high sensitivity.

It is feasible with current experimental technology.

The method effectively distinguishes singlet and triplet states.

Abstract

We outline a scheme to accomplish measurements of a solid state double well system (DWS) with both one and two electrons in non-localised bases. We show that, for a single particle, measuring the local charge distribution at the midpoint of a DWS using an SET as a sensitive electrometer amounts to performing a projective measurement in the parity (symmetric/antisymmetric) eigenbasis. For two-electrons in a DWS, a similar configuration of SET results in close-to-projective measurement in the singlet/triplet basis. We analyse the sensitivity of the scheme to asymmetry in the SET position for some experimentally relevant parameter, and show that it is realisable in experiment.