Optically Loaded Semiconductor Quantum Memory Register

Kim, Danny; Kiselev, A. A.; Ross, Richard S.; Rakher, Matthew T.; Jones, Cody; Ladd, Thaddeus D.

doi:10.1103/physrevapplied.5.024014

Cited by 10 publications

(11 citation statements)

References 101 publications

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“…While the overhead associated with mitigating nuclear-spin-induced decoherence remains a disadvantage 5 , GaAs quantum dot devices currently tend to be more reproducible and require less challenging lithographic feature sizes. Furthermore, they avoid the complication of several near-degenerate conduction band valleys and are better suited for the conversion between spin states and flying photonic qubits due to the direct band gap 35 , 36 . Given that GaAs has certain advantages over Si (but also other disadvantages), our study contributes to a well-founded comparison of the two material systems.…”

Section: Discussionmentioning

confidence: 99%

Closed-loop control of a GaAs-based singlet-triplet spin qubit with 99.5% gate fidelity and low leakage

et al. 2020

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Semiconductor spin qubits have recently seen major advances in coherence time and control fidelities, leading to a single-qubit performance that is on par with other leading qubit platforms. Most of this progress is based on microwave control of single spins in devices made of isotopically purified silicon. For controlling spins, the exchange interaction is an additional key ingredient which poses new challenges for high-fidelity control. Here, we demonstrate exchange-based single-qubit gates of two-electron spin qubits in GaAs double quantum dots. Using careful pulse optimization and closed-loop tuning, we achieve a randomized benchmarking fidelity of (99.50±0.04)% and a leakage rate of 0.13% out of the computational subspace. These results open new perspectives for microwave-free control of singlet-triplet qubits in GaAs and other materials.

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Section: Discussionmentioning

confidence: 99%

Closed-loop control of a GaAs-based singlet-triplet spin qubit with 99.5% gate fidelity and low leakage

et al. 2020

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“…This capability could be a major advantage over Si by allowing the realization of networks of quantum processors for communication and distributed computing and by opening additional options for long-range on-chip coupling. Much of the fundamental principles have been demonstrated using self-assembled QDs and could be transferred to hybrid devices with some kind of exciton trap coupled to a gate-defined dot [62]. However, such devices yet remain to be realized.…”

Section: Advances In Science and Technology To Meet Challengesmentioning

confidence: 99%

Roadmap on quantum nanotechnologies

Laucht¹,

Hohls²,

Ubbelohde³

et al. 2021

Nanotechnology

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Quantum phenomena are typically observable at length and time scales smaller than those of our everyday experience, often involving individual particles or excitations. The past few decades have seen a revolution in the ability to structure matter at the nanoscale, and experiments at the single particle level have become commonplace. This has opened wide new avenues for exploring and harnessing quantum mechanical effects in condensed matter. These quantum phenomena, in turn, have the potential to revolutionize the way we communicate, compute and probe the nanoscale world. Here, we review developments in key areas of quantum research in light of the nanotechnologies that enable them, with a view to what the future holds. Materials and devices with nanoscale features are used for quantum metrology and sensing, as building blocks for quantum computing, and as sources and detectors for quantum communication. They enable explorations of quantum behaviour and unconventional states in nano-and opto-mechanical systems, low-dimensional systems, molecular devices, nano-plasmonics, quantum electrodynamics, scanning tunnelling microscopy, and more. This rapidly expanding intersection of nanotechnology and quantum science/technology is mutually beneficial to both fields, laying claim to some of the most exciting scientific leaps of the last decade, with more on the horizon.

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“…Self-assembled quantum dots are more challenging than ions to integrate into coupled arrays, but such integration is needed to effectively implement the communication protocols. See [90] for a hardware proposal combining demonstrated quantum dot spin-photon methods with demonstrated methods for constructing multi-qubit arrays.…”

Section: Bsamentioning

confidence: 99%

Design and analysis of communication protocols for quantum repeater networks

et al. 2016

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We analyze how the performance of a quantum-repeater network depends on the protocol employed to distribute entanglement, and we find that the choice of repeater-to-repeater link protocol has a profound impact on entanglement-distribution rate as a function of hardware parameters. We develop numerical simulations of quantum networks using different protocols, where the repeater hardware is modeled in terms of key performance parameters, such as photon generation rate and collection efficiency. These parameters are motivated by recent experimental demonstrations in quantum dots, trapped ions, and nitrogen-vacancy centers in diamond. We find that a quantum-dot repeater with the newest protocol ('MidpointSource') delivers the highest entanglement-distribution rate for typical cases where there is low probability of establishing entanglement per transmission, and in some cases the rate is orders of magnitude higher than other schemes. Our simulation tools can be used to evaluate communication protocols as part of designing a large-scale quantum network. succinctly, managing photon loss is crucial for designing quantum networks, and the interference and detection of two single-photon signals enables reliable determination of whether a signal was received or lost in transmission while also being more robust to path-length fluctuations than single-detection schemes [28,48].The paper begins with some preliminary considerations for distributing entanglement in section 2. Section 3 examines three protocols for establishing entanglement between repeaters, and we simulate the performance of these protocols in section 4 using hardware parameters representative of recent experimental work. Section 5 summarizes our results and discusses related communication schemes that we chose not to examine, though they are appropriate for future work. PreliminariesWe begin by listing a few features common to any of the repeaters we consider. As shown in figure 1, each repeater has some number of controllable memory qubits that must have long coherence times (of order 10 ms) and low-error gates to act on these memory qubits (error per gate below 0.1%). The memory qubits may be protected with error correction [16,[24][25][26][27] to extend their coherence time or suppress gate error. Furthermore, there is an interface for generating an entangled state between a memory qubit and a single-photonic qubit. We will simply say photon to mean a photonic qubit, since there is no ambiguity in this paper. For example, memory/photon entangled states have been demonstrated for ions, NV centers in diamond, and quantum dots [29,36,37,39,[41][42][43]49]. The memory/photon entanglement is a resource for generating entanglement between repeaters, by swapping entanglement using the photons (described below).Each quantum repeater in a network has multiple optical links to its neighbors. In this paper, we focus on protocols for efficiently distributing entanglement across the link between two repeaters. As in figure 1, each repeater will devote some of its memo...

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Optically Loaded Semiconductor Quantum Memory Register

Cited by 10 publications

References 101 publications

Closed-loop control of a GaAs-based singlet-triplet spin qubit with 99.5% gate fidelity and low leakage

Closed-loop control of a GaAs-based singlet-triplet spin qubit with 99.5% gate fidelity and low leakage

Roadmap on quantum nanotechnologies

Design and analysis of communication protocols for quantum repeater networks

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