Decoherence enhanced quantum measurement of a quantum dot spin qubit

Abstract

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.

5 pages, 1 figure

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Cited by in corpus (6)

• A scheme for direct detection of qubit-environment entanglement generated during qubit pure dephasing
• Enhanced Quantum Metrology with Non-Phase-Covariant Noise
• System-environment correlations for dephasing two-qubit states coupled to thermal baths
• Oscillating properties of a two-electron quantum dot in the presence of a magnetic field
• 3D two-electron double quantum dot: comparison between the behavior of some physical quantities under two different confinement potentials in the presence of a magnetic field
• Triplet-assisted leakage during singlet-triplet qubit readout with a quantum point contact