Proposal of a full Bell state analyzer for spin qubits in a double quantum dot

TL;DR

This paper proposes a scheme for complete Bell state measurement of spin qubits in double quantum dots using spin-blockade and electron-spin resonance, leveraging g-factor engineering for improved accuracy.

Contribution

It introduces a novel method combining spin-blockade and biaxial electron-spin resonance with g-factor engineering to enable full Bell state measurement of spin qubits.

Findings

Sequential spin-to-charge conversions facilitate Bell state measurement.

g-factor engineering allows swapping of triplet and singlet states without disturbance.

The scheme enhances measurement capabilities for spin qubits in quantum dots.

Abstract

We propose a scheme for full Bell state measurement of spin qubits in a double quantum dot. Our scheme consists of Pauli spin-blockade measurements and biaxial electron-spin resonance. In order to eliminate the average of the Zeeman fields, the double quantum dot is designed so that the Land\'e g-factors of first and second dots satisfy g1=g2 with the use of g-factor engineering. Thus, we can swap one of the three spin-triplet states for the spin-singlet state without disturbing the other states. Our study shows that the sequential spin-to-charge conversions enable us to implement the full Bell state measurement of electron-spin qubits.