Coherent spin qubit transport in silicon

Yoneda, Jun; Huang, W.; Feng, MengKe; Yang, C. H.; Chan, KW; Tanttu, Tuomo; Gilbert, Will; Leon, Ross C. C.; Hudson, Fay E.; Itoh, Kohei M.; Morello, Andrea; Bartlett, Stephen D.; Laucht, Arne; Saraiva, André; Dzurak, Andrew S.

doi:10.1038/s41467-021-24371-7

Cited by 76 publications

(63 citation statements)

References 58 publications

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“…We focus on tunnel couplings t c larger than 20 µeV, as these have been experimentally reported for silicon charge shuttling [57]. A tunnel coupling of order 100 µeV was reported in [59], suggesting that even larger values are realistic.…”

Section: Model Parameters and Detailsmentioning

confidence: 85%

“…Coherent spin shuttling has been realized over effective several-micrometer distances in a GaAs quantum dot circuit [56]. Reliable charge shuttling has also been shown in multi-dot Si/SiGe arrays [57,58], while repeated coherent spin tunneling between two Si-MOS dots has also been demonstrated [59]. This places shuttling as a top candidate for micron-scale on-chip quantum information transport in near-term devices.…”

Section: Shuttlingmentioning

confidence: 95%

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Multicore Quantum Computing

Jnane,

Undseth,

Cai

et al. 2022

Preprint

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Any architecture for practical quantum computing must be scalable. An attractive approach is to create multiple cores, computing regions of fixed size that are well-spaced but interlinked with communication channels. This exploded architecture can relax the demands associated with a single monolithic device: the complexity of control, cooling and power infrastructure as well as the difficulties of cross-talk suppression and near-perfect component yield. Here we explore interlinked multicore architectures through analytic and numerical modelling. While elements of our analysis are relevant to diverse platforms, our focus is on semiconductor electron spin systems in which numerous cores may exist on a single chip. We model shuttling and microwave-based interlinks and estimate the achievable fidelities, finding values that are encouraging but markedly inferior to intra-core operations. We therefore introduce optimsed entanglement purification to enable highfidelity communication, finding that 99.5% is a very realistic goal. We then assess the prospects for quantum advantage using such devices in the NISQ-era and beyond: we simulate recently proposed exponentially-powerful error mitigation schemes in the multicore environment and conclude that these techniques impressively suppress imperfections in both the inter-and intra-core operations.

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Section: Model Parameters and Detailsmentioning

confidence: 85%

Section: Shuttlingmentioning

confidence: 95%

Multicore Quantum Computing

Jnane,

Undseth,

Cai

et al. 2022

Preprint

View full text Add to dashboard Cite

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“…The transition dynamics of a driven quantum system in the vicinity of avoided crossings of its energy levels [1][2][3][4] is at the heart of various very different physical problems. Examples are the dynamics of chemical reactions [5], the spin reversal dynamics in molecular nanomagnets [6], the non-equilibrium dynamics of glasses at low temperatures [7][8][9][10], the dynamics of solid state artificial atoms [11,12], and transfer of information between distant electron spin qubits [13][14][15][16][17][18][19]. Typically, quantum systems are also influenced by their environments which exert fluctuating forces on them resulting in decoherence and relaxation [20,21].…”

Section: Introductionmentioning

confidence: 99%

Crossing time in the dissipative Landau–Zener quantum dynamics

Nalbach

2022

Eur. Phys. J. B

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We study the dynamics of a quantum two-state system driven through an avoided crossing under the influence of a super-Ohmic environment. We determine the Landau–Zener probability employing the numerical exact quasi-adiabatic path integral and a Markovian weak coupling approach. Increasing the driving time in the numerical protocol, we find converged results which shows that super-Ohmic environments only influence the Landau Zener probability within a finite crossing time window. This crossing time is qualitatively determined by the environmental cut-off energy. At weak coupling, we show that the Markovian weak coupling approach provides an accurate description. Since pure dephasing of a super-Ohmic bath is non-Markovian, this highlights that pure dephasing hardly influences the Landau–Zener probability. The finite crossing time window, thus, results from the suppression of relaxation once the energy splitting exceeds the environmental cut-off energy. Graphical abstract

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“…In addition, the ∼ 100 nm spatial dimensions intrinsic to semiconductor spin qubits provide the potential to pack many millions of qubits inside a single quantum processor chip. The last several years have seen significant progress in spin-qubit research that resulted in the demonstration of long coherence times [3], high-fidelity single- [3][4][5] and two-qubit gates [6,7], quantum algorithms [8], quantum non-demolition measurements [9,10], and electron spin [11] and charge [12,13] transfer.…”

Section: Introductionmentioning

confidence: 99%

The spider-web array--a sparse spin qubit array

Boter,

Dehollain,

van Dijk

et al. 2021

Preprint

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One of the main bottlenecks in the pursuit of a large-scale-chip-based quantum computer is the large number of control signals needed to operate qubit systems. As system sizes scale up, the number of terminals required to connect to off-chip control electronics quickly becomes unmanageable. Here, we discuss a quantum-dot spin-qubit architecture that integrates on-chip control electronics, allowing for a significant reduction in the number of signal connections at the chip boundary. By arranging the qubits in a two-dimensional (2D) array with ∼12 µm pitch, we create space to implement locally integrated sample-and-hold circuits. This allows to offset the inhomogeneities in the potential landscape across the array and to globally share the majority of the control signals for qubit operations. We make use of advanced circuit modeling software to go beyond conceptual drawings of the component layout, to assess the feasibility of the scheme through a concrete floor plan, including estimates of footprints for quantum and classical electronics, as well as routing of signal lines across the chip using different interconnect layers. We make use of local demultiplexing circuits to achieve an efficient signal-connection scaling leading to a Rent's exponent as low as p = 0.43. Furthermore, we use available data from state-of-the-art spin qubit and microelectronics technology development, as well as circuit models and simulations, to estimate the operation frequencies and power consumption of a million-qubit processor. This work presents a novel and complementary approach to previously proposed architectures, focusing on a feasible scheme to integrating quantum and classical hardware, and significantly closing the gap towards a fully CMOS-compatible quantum computer implementation.

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Coherent spin qubit transport in silicon

Cited by 76 publications

References 58 publications

Multicore Quantum Computing

Multicore Quantum Computing

Crossing time in the dissipative Landau–Zener quantum dynamics

The spider-web array--a sparse spin qubit array

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