Quantum error correction in a solid-state hybrid spin register

Waldherr, G.; Wang, Y.; Zaiser, Sebastian; Jamali, Mohammad Vahid; Schulte‐Herbrüggen, Thomas; Abe, Hiroshi; Ohshima, Takeshi; Isoya, Junichi; Du, Jiangfeng; Neumann, Philipp; Wrachtrup, Jörg

doi:10.1038/nature12919

Cited by 585 publications

(667 citation statements)

References 41 publications

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“…As has been mentioned in the introductory part, the generation of optically active spins is important for solid-state quantum ARTICLE computing and communications, sensing, precision measurement and so on [1][2][3][4][5]12,16,23 . Very recently, single emitters in the visible spectral range have been isolated in SiC wafers 20 and nanoparticles 35 .…”

Section: Discussionmentioning

confidence: 99%

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Engineering near-infrared single-photon emitters with optically active spins in ultrapure silicon carbide

et al. 2015

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Vacancy-related centres in silicon carbide are attracting growing attention because of their appealing optical and spin properties. These atomic-scale defects can be created using electron or neutron irradiation; however, their precise engineering has not been demonstrated yet. Here, silicon vacancies are generated in a nuclear reactor and their density is controlled over eight orders of magnitude within an accuracy down to a single vacancy level. An isolated silicon vacancy serves as a near-infrared photostable single-photon emitter, operating even at room temperature. The vacancy spins can be manipulated using an optically detected magnetic resonance technique, and we determine the transition rates and absorption crosssection, describing the intensity-dependent photophysics of these emitters. The on-demand engineering of optically active spins in technologically friendly materials is a crucial step toward implementation of both maser amplifiers, requiring high-density spin ensembles, and qubits based on single spins.

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Section: Discussionmentioning

confidence: 99%

“…Q uantum emitters hosted in crystalline lattices are highly attractive candidates for quantum information processing 1 , secure networks 2,3 and nanosensing 4,5 . For many of these applications it is necessary to have control over single emitters with long spin coherence times.…”

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confidence: 99%

Engineering near-infrared single-photon emitters with optically active spins in ultrapure silicon carbide

et al. 2015

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“…Using phonons as flying qubits is the first step in the exploration of multiple degrees-of-freedom electron-phonon systems. Possible future works would investigate CNT mechanical resonator arrays in phononic quantum memories [42], also many-body interactions [43] and the implementation of possible quantum error correction schemes in coupled spin-phonon chains [44]. This system can even be further integrated with superconducting circuits to construct a hybrid quantum machine [45,46].…”

Section: Figmentioning

confidence: 99%

Strongly Coupled Nanotube Electromechanical Resonators

et al. 2016

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Coupling an electromechanical resonator with carbon-nanotube quantum dots is a significant method to control both the electronic charge and the spin quantum states. By exploiting a novel micro-transfer technique, we fabricate two strongly-coupled and electrically-tunable mechanical resonators on a single carbon nanotube for the first time. The frequency of the two resonators can be individually tuned by the bottom gates, and strong coupling is observed between the charge states and phonon modes of each resonator. Furthermore, the conductance of either resonator can be nonlocally modulated by the phonon modes in the other resonator. Strong coupling is observed between the phonon modes of the two resonators, which provides an effective long distance electron-electron interaction. The generation of phonon-mediated-spin entanglement is also analyzed for the two resonators. This strongly-coupled nanotube electromechanical resonator array provides an experimental platform for studying the coherent electron-phonon interaction, the phonon mediated long-distance electron interaction, and entanglement state generation.

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“…In contrast to open-loop dynamical decoupling (DD) techniques [10], feedback control can protect the qubit even against Markovian noise and for an arbitrary period of time (limited only by the ancilla coherence time), while allowing gate operations. It is thus more closely related to Quantum Error Correction schemes [11][12][13][14], which however require larger and increasing qubit overheads. Increasing the number of fresh ancillas allows protection even beyond their coherence time.…”

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confidence: 99%

Coherent feedback control of a single qubit in diamond

Hirose

Cappellaro

2016

Nature

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Engineering desired operations on qubits subjected to the deleterious effects of their environment is a critical task in quantum information processing, quantum simulation and sensing. The most common approach is to rely on open-loop quantum control techniques, including optimal control algorithms, based on analytical [1] or numerical [2] solutions, Lyapunov design [3] and Hamiltonian engineering [4]. An alternative strategy, inspired by the success of classical control, is feedback control [5]. Because of the complications introduced by quantum measurement [6], closed-loop control is less pervasive in the quantum settings and, with exceptions [7,8], its experimental implementations have been mainly limited to quantum optics experiments. Here we implement a feedback control algorithm with a solid-state spin qubit system associated with the Nitrogen Vacancy (NV) centre in diamond, using coherent feedback [9] to overcome limitations of measurement-based feedback, and show that it can protect the qubit against intrinsic dephasing noise for milliseconds. In coherent feedback, the quantum system is connected to an auxiliary quantum controller (ancilla) that acquires information about the system's output state (by an entangling operation) and performs an appropriate feedback action (by a conditional gate). In contrast to open-loop dynamical decoupling (DD) techniques [10], feedback control can protect the qubit even against Markovian noise and for an arbitrary period of time (limited only by the ancilla coherence time), while allowing gate operations. It is thus more closely related to Quantum Error Correction schemes [11][12][13][14], which however require larger and increasing qubit overheads. Increasing the number of fresh ancillas allows protection even beyond their coherence time. We can further evaluate the robustness of the feedback protocol, which could be applied to quantum computation and sensing, by exploring an interesting tradeoff between information gain and decoherence protection, as measurement of the ancilla-qubit correlation after the feedback algorithm voids the protection, even if the rest of the dynamics is unchanged.To demonstrate coherent feedback with spin qubits, we choose two of the most common tasks for qubits, implementing the no-operation (NOOP) and NOT gates, while cancelling the effects of noise. A simple, measurementbased feedback scheme, exploiting one ancillary qubit, was proposed in [16]. The correction protocol (Fig. 1a) works by entangling the qubit-ancilla system before the desired gate operation. By selecting an entangling operation U c appropriate for the type of bath acting on the system, information about the noise action is encoded in the ancilla state. After undoing the entangling operation, the qubit coherence can be restored by a feedback action, Hadamard gates prepare and read out a superposition state of the qubit, |φ q = 1 √ 2 (|0 + |1 ). Amid entangling gates between qubit and ancilla, the qubit is subjected to noise (and possibly unitary gates U ). We assume the ancil...

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Quantum error correction in a solid-state hybrid spin register

Cited by 585 publications

References 41 publications

Engineering near-infrared single-photon emitters with optically active spins in ultrapure silicon carbide

Engineering near-infrared single-photon emitters with optically active spins in ultrapure silicon carbide

Strongly Coupled Nanotube Electromechanical Resonators

Coherent feedback control of a single qubit in diamond

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