Coherent control of electron spin qubits in silicon using a global field

Vahapoglu, Ensar; Slack-Smith, James P.; Leon, Ross C. C.; Lim, Wee Han; Hudson, Fay E.; Day, T.; D., Cifuentes, Jesus; Tanttu, Tuomo; Yang, C. H.; Saraiva, André; Абросимов, Н. В.; Pohl, H.‐J.; Thewalt, M. L. W.; Laucht, Arne; Dzurak, A. S.; Pla, Jarryd

doi:10.1038/s41534-022-00645-w

Cited by 16 publications

(8 citation statements)

References 46 publications

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“…The voltage differences Δ between the transitions in Figure a are extracted and plotted in Figure 4b. [ 51,52 ] Before the 16th‐to‐17th transition, there is no clear spin structure visible, in contrast to what we have previously observed in a circular quantum dot. [ 53 ] This lack of structure is explained by disorder in the device and the complicated interactions between the electrons of the three artificial atoms.…”

Section: Spin Structure Of the Jellybean Dotcontrasting

confidence: 86%

Jellybean Quantum Dots in Silicon for Qubit Coupling and On‐Chip Quantum Chemistry

et al. 2023

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The small size and excellent integrability of silicon metal–oxide–semiconductor (SiMOS) quantum dot spin qubits make them an attractive system for mass‐manufacturable, scaled‐up quantum processors. Furthermore, classical control electronics can be integrated on‐chip, in‐between the qubits, if an architecture with sparse arrays of qubits is chosen. In such an architecture qubits are either transported across the chip via shuttling or coupled via mediating quantum systems over short‐to‐intermediate distances. This paper investigates the charge and spin characteristics of an elongated quantum dot—a so‐called jellybean quantum dot—for the prospects of acting as a qubit–qubit coupler. Charge transport, charge sensing, and magneto‐spectroscopy measurements are performed on a SiMOS quantum dot device at mK temperature and compared to Hartree–Fock multi‐electron simulations. At low electron occupancies where disorder effects and strong electron–electron interaction dominate over the electrostatic confinement potential, the data reveals the formation of three coupled dots, akin to a tunable, artificial molecule. One dot is formed centrally under the gate and two are formed at the edges. At high electron occupancies, these dots merge into one large dot with well‐defined spin states, verifying that jellybean dots have the potential to be used as qubit couplers in future quantum computing architectures.

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Section: Spin Structure Of the Jellybean Dotcontrasting

confidence: 86%

Jellybean Quantum Dots in Silicon for Qubit Coupling and On‐Chip Quantum Chemistry

et al. 2023

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“…66 . It requires placing the structure inside a broadband 3D microwave cavity designed to deliver an oscillatory magnetic field perpendicular to the external magnetic field at the location of the chip 67,68 . The cavity is designed to have a quality factor Q ≤ 100 to cover the range of potential qubit frequencies associated with the typical variations of the g-factor of electrons in MOS devices, Δg/g ≈ 10 −2 (Ref.…”

Section: Architecture Embodiment In Silicon: Single-qubit Operationsmentioning

confidence: 99%

Compilation and scaling strategies for a silicon quantum processor with sparse two-dimensional connectivity

et al. 2023

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Inspired by the challenge of scaling-up existing silicon quantum hardware, we propose a 2d spin-qubit architecture with low compilation overhead. The architecture is based on silicon nanowire split-gate transistors which form 1d chains of spin-qubits and allow the execution of two-qubit operations among neighbors. We introduce a silicon junction which can couple four nanowires into 2d arrangements via spin shuttling and Swap operations. We then propose a modular sparse 2d spin-qubit architecture with unit cells of diagonally-oriented squares with nanowires along the edges and junctions on the corners. Targeting noisy intermediate-scale quantum (NISQ) demonstrators, we show that the proposed architecture allows for compilation strategies which outperform methods for 1d chains, and exhibits favorable scaling properties which enable trading-off compilation overhead and colocation of control electronics within each square by adjusting the nanowire length. An appealing feature of the proposed architecture is its manufacturability using complementary-metal-oxide-semiconductor (CMOS) fabrication processes.

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“…Electric driving requires a large spin–orbit coupling, which exposes the spins to the impact of charge impurities. In this paper we focus on spin qubits driven magnetically 4 , 29 , which do not have this requirement. These qubits can be controlled coherently without the inclusion of micromagnets, thus preserving the low spin–orbit coupling of electrons in silicon and protecting the spin from electric fluctuations.…”

Section: Introductionmentioning

confidence: 99%

“…The double quantum dots are formed under the gates P1, P2 or P2, P3 depending on the device. In one of the devices the qubits were driven magnetically with a dielectric resonator instead of an antenna 29 , 70 . A vector magnet enabled rotations of the magnetic field for the measurements in two of the devices.…”

Section: Introductionmentioning

confidence: 99%

Bounds to electron spin qubit variability for scalable CMOS architectures

Cifuentes,

Tanttu,

Gilbert

et al. 2024

Nat Commun

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Spins of electrons in silicon MOS quantum dots combine exquisite quantum properties and scalable fabrication. In the age of quantum technology, however, the metrics that crowned Si/SiO2 as the microelectronics standard need to be reassessed with respect to their impact upon qubit performance. We chart spin qubit variability due to the unavoidable atomic-scale roughness of the Si/SiO2 interface, compiling experiments across 12 devices, and develop theoretical tools to analyse these results. Atomistic tight binding and path integral Monte Carlo methods are adapted to describe fluctuations in devices with millions of atoms by directly analysing their wavefunctions and electron paths instead of their energy spectra. We correlate the effect of roughness with the variability in qubit position, deformation, valley splitting, valley phase, spin-orbit coupling and exchange coupling. These variabilities are found to be bounded, and they lie within the tolerances for scalable architectures for quantum computing as long as robust control methods are incorporated.

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Coherent control of electron spin qubits in silicon using a global field

Cited by 16 publications

References 46 publications

Jellybean Quantum Dots in Silicon for Qubit Coupling and On‐Chip Quantum Chemistry

Jellybean Quantum Dots in Silicon for Qubit Coupling and On‐Chip Quantum Chemistry

Compilation and scaling strategies for a silicon quantum processor with sparse two-dimensional connectivity

Bounds to electron spin qubit variability for scalable CMOS architectures

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