Decoherence enhanced quantum measurement of a quantum dot spin qubit

We study the effect of phonons on a proposed scheme for the direct measurement of two-electron spin states in a double quantum dot by monitoring the the noise of the current flowing through a quantum point contact coupled to one of the dots. We show that although the effect of phonons is damaging to...

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Bibliographic Details
Published in:arXiv.org 2013-12
Main Authors: Roszak, Katarzyna, Marcinowski, Łukasz, Machnikowski, Paweł
Format: Article
Language:English
Subjects:
Electron spin
Electrons
Noise
Noise monitoring
Phonons
Point contact
Quantum dots
Qubits (quantum computing)
Online Access:Get full text
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Summary:We study the effect of phonons on a proposed scheme for the direct measurement of two-electron spin states in a double quantum dot by monitoring the the noise of the current flowing through a quantum point contact coupled to one of the dots. We show that although the effect of phonons is damaging to the procedure at extremely low temperatures characteristic of spin-in-quantum-dots experiments, and may even be fatal, increasing the temperature leads to a revival of the schemes usefulness. Furthermore, at higher, but still reasonably low temperatures phonon effects become advantageous to the measurement scheme, and lead to the enhancement of the spin-singlet noise without disturbing the low spin-triplet noise. Hence, the uncontrollable interaction of the measured system with the open bosonic environment, can be harnessed to increase the distinguishability between the measured states.
ISSN:2331-8422
DOI:10.48550/arxiv.1312.0830