Quantum and Tunnelling Capacitance in Charge and Spin Qubits

We present a theoretical analysis of the capacitance of a double quantum dot in the charge and spin qubit configurations probed at high-frequencies. We find that in general the total capacitance of the system consists of two state-dependent terms: The quantum capacitance arising from adiabatic charg...

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Bibliographic Details
Published in:arXiv.org 2016-08
Main Authors: Mizuta, R, Otxoa, R M, Betz, A C, Gonzalez-Zalba, M F
Format: Article
Language:English
Subjects:
Capacitance
Electron energy
Electron spin
Frequency analysis
Mathematical analysis
Quantum dots
Qubits (quantum computing)
Online Access:Get full text
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Summary:We present a theoretical analysis of the capacitance of a double quantum dot in the charge and spin qubit configurations probed at high-frequencies. We find that in general the total capacitance of the system consists of two state-dependent terms: The quantum capacitance arising from adiabatic charge motion and the tunnelling capacitance that appears when repopulation occurs at a rate comparable or faster than the probing frequency. The analysis of the capacitance lineshape as a function of externally controllable variables offers a way to characterize the qubits' charge and spin state as well as relevant system parameters such as charge and spin relaxation times, tunnel coupling, electron temperature and electron g-factor. Overall, our analysis provides a formalism to understand dispersive qubit-resonator interactions which can be applied to high-sensitivity and non-invasive quantum-state readout.
ISSN:2331-8422
DOI:10.48550/arxiv.1604.02884