Proposed Five-Electron Charge Quadrupole Qubit

A charge qubit couples to environmental electric field fluctuations through its dipole moment, resulting in fast decoherence. We propose the p orbital (pO) qubit, formed by the single electron, p-like valence states of a five-electron Si quantum dot, which couples to charge noise through the quadrup...

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Bibliographic Details
Published in:arXiv.org 2024-11
Main Authors: Caporaletti, John H, Kestner, J P
Format: Article
Language:English
Subjects:
Dipole moments
Electric fields
Q factors
Quadrupole interaction
Quadrupoles
Quantum dots
Qubits (quantum computing)
Rabi frequency
Single electrons
Valence
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Summary:A charge qubit couples to environmental electric field fluctuations through its dipole moment, resulting in fast decoherence. We propose the p orbital (pO) qubit, formed by the single electron, p-like valence states of a five-electron Si quantum dot, which couples to charge noise through the quadrupole moment. We demonstrate that the pO qubit offers distinct advantages in quality factor, gate speed, readout and size. We use a phenomenological, dipole two-level-fluctuator charge noise model to estimate a \(T_2^* \sim 80\) ns. In conjunction with Rabi frequencies of order 10 GHz, an order of magnitude improvement in qubit quality factor is expected relative to state-of-the-art semiconductor spin qubits. The pO qubit features all-electrical control via modulating the dot's eccentricity. We also show how to perform two-qubit gates via the \(1/r^5\) quadrupole-quadrupole interaction. We find a universal gate set using gradient ascent based control pulse optimization, subject to 10 GHz maximum allowable bandwidth and 1 ns pulse times.
ISSN:2331-8422