Fully Tunable Hyperfine Interactions of Hole Spin Qubits in Si and Ge Quantum Dots

Bosco, Stefano; Loss, Daniel

doi:10.1103/physrevlett.127.190501

Cited by 44 publications

(35 citation statements)

References 69 publications

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“…We conclude that the intrinsic material charge noise might be limiting coherence in some of these experiments, while in some, such as Si FinFETs, the nuclear noise is still the limiting factor, see Refs. [15,18]. Our results suggest that holes in planar dots can reach coherence comparable to electrons 6 , and searching for the hole-qubit sweet spots experimentally looks attractive.…”

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confidence: 74%

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Charge-noise induced dephasing in silicon hole-spin qubits

Malkoc,

Stano,

Loss

2022

Preprint

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We investigate theoretically charge-noise induced spin dephasing of a hole confined in a quasi-twodimensional silicon quantum dot. Central to our treatment is accounting for higher-order corrections to the Luttinger Hamiltonian. Using experimentally reported parameters, we find that the new terms give rise to sweet-spots for the hole-spin dephasing, which are sensitive to device details: dot size and asymmetry, growth direction, and applied magnetic and electric fields. Furthermore, we estimate that the dephasing time at the sweet-spots is boosted by several orders of magnitude, up to order of milliseconds.

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confidence: 74%

“…Holes also offer stronger spin-orbit coupling [13][14][15][16], essential for electric spin control without micromagnets or on-chip ESR lines [17]. Taken together, the reduced susceptibility to nuclear noise [18], the absence of valley degeneracy, and fully-electric control make holes in silicon a very attractive platform for scalable spin qubits.…”

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confidence: 99%

Charge-noise induced dephasing in silicon hole-spin qubits

Malkoc,

Stano,

Loss

2022

Preprint

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“…The hyperfine interactions between the hole and the N nuclei spins are described by the following Hamiltonian 54,55 :…”

Section: S7 Hyperfine Interaction Limit For the Inhomogeneous Dephasi...mentioning

confidence: 99%

“…The above expression can be evaluated with the 6 bands k • p wave functions computed in section S2. For silicon, we use n0 = 49.94 nm −3 , as well as ν = 4.7%, I = 1/2, and |A| = 1.67 µeV for 29 Si isotopes 55 . This value of |A| was specifically computed for holes with ab initio density functional theory 59 .…”

Section: S7 Hyperfine Interaction Limit For the Inhomogeneous Dephasi...mentioning

confidence: 99%

A single hole spin with enhanced coherence in natural silicon

Piot¹,

B.²,

Schmitt³

et al. 2022

Preprint

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Semiconductor spin qubits based on spin-orbit states are responsive to electric field excitation allowing for practical, fast and potentially scalable qubit control. Spinelectric susceptibility, however, renders these qubits generally vulnerable to electrical noise, which limits their coherence time. Here we report on a spin-orbit qubit consisting of a single hole electrostatically confined in a natural silicon metal-oxidesemiconductor device. By varying the magnetic field orientation, we reveal the existence of operation sweet spots where the impact of charge noise is minimized while preserving an efficient electric-dipole spin control. We correspondingly observe an extension of the Hahn-echo coherence time up to 88 µs, exceeding by an order of magnitude the best reported values for hole-spin qubits, and approaching the state-of-the-art for electron spin qubits with synthetic spin-orbit coupling in isotopically-purified silicon. This finding largely enhances the prospects of silicon-based hole spin qubits for scalable quantum information processing.

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“…Spin qubits in silicon (Si) and germanium (Ge) quantum dots are frontrunner candidates to process quantum information [1][2][3][4][5][6]. Hole spin qubits hold particular promise because of their large and fully tunable spin-orbit interactions (SOI) [7][8][9][10][11][12][13][14][15], enabling ultrafast all-electrical gates at low power [16][17][18][19][20][21][22][23][24][25], and because of their resilience to hyperfine noise even in natural materials [26][27][28][29][30][31]. In current quantum processors, engineering long-range interactions of distant qubits remains a critical challenge.…”

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confidence: 99%

Fully tunable longitudinal spin-photon interactions in Si and Ge quantum dots

Bosco,

Scarlino,

Klinovaja

et al. 2022

Preprint

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Spin qubits in silicon and germanium quantum dots are promising platforms for quantum computing, but entangling spin qubits over micrometer distances remains a critical challenge. Current prototypical architectures maximize transversal interactions between qubits and microwave resonators, where the spin state is flipped by nearly resonant photons. However, these interactions cause back-action on the qubit, that yield unavoidable residual qubit-qubit couplings and significantly affect the gate fidelity. Strikingly, residual couplings vanish when spin-photon interactions are longitudinal and photons couple to the phase of the qubit. We show that large longitudinal interactions emerge naturally in state-of-the-art hole spin qubits. These interactions are fully tunable and can be parametrically modulated by external oscillating electric fields. We propose realistic protocols to measure these interactions and to implement fast and high-fidelity two-qubit entangling gates. These protocols work also at high temperatures, paving the way towards the implementation of large-scale quantum processors.

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Fully Tunable Hyperfine Interactions of Hole Spin Qubits in Si and Ge Quantum Dots

Cited by 44 publications

References 69 publications

Charge-noise induced dephasing in silicon hole-spin qubits

Charge-noise induced dephasing in silicon hole-spin qubits

A single hole spin with enhanced coherence in natural silicon

Fully tunable longitudinal spin-photon interactions in Si and Ge quantum dots

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