Towards quantum networks of single spins: analysis of a quantum memory with an optical interface in diamond

2015 ◽  
Vol 184 ◽  
pp. 173-182 ◽  
Author(s):  
M. S. Blok ◽  
N. Kalb ◽  
A. Reiserer ◽  
T. H. Taminiau ◽  
R. Hanson
Keyword(s):  
Quantum Information Processing ◽  
Quantum States ◽  
Nitrogen Vacancy ◽  
Nuclear Spins ◽  
Quantum Repeater ◽  
Quantum Networks ◽  
Entanglement Generation ◽  
Quantum Bit ◽  
Single Defect ◽  
Coupling Parameters

Single defect centers in diamond have emerged as a powerful platform for quantum optics experiments and quantum information processing tasks. Connecting spatially separated nodes via optical photons into a quantum network will enable distributed quantum computing and long-range quantum communication. Initial experiments on trapped atoms and ions as well as defects in diamond have demonstrated entanglement between two nodes over several meters. To realize multi-node networks, additional quantum bit systems that store quantum states while new entanglement links are established are highly desirable. Such memories allow for entanglement distillation, purification and quantum repeater protocols that extend the size, speed and distance of the network. However, to be effective, the memory must be robust against the entanglement generation protocol, which typically must be repeated many times. Here we evaluate the prospects of using carbon nuclear spins in diamond as quantum memories that are compatible with quantum networks based on single nitrogen vacancy (NV) defects in diamond. We present a theoretical framework to describe the dephasing of the nuclear spins under repeated generation of NV spin-photon entanglement and show that quantum states can be stored during hundreds of repetitions using typical experimental coupling parameters. This result demonstrates that nuclear spins with weak hyperfine couplings are promising quantum memories for quantum networks.

Quantum-entanglement storage and extraction in quantum network node

2018 ◽  
Vol 16 (01) ◽  
pp. 1850009 ◽  
Author(s):  
ZhuoYu Shan ◽  
Yong Zhang
Keyword(s):  
Information Processing ◽  
Quantum Information ◽  
Quantum Entanglement ◽  
Information Technologies ◽  
Quantum Information Processing ◽  
Bell State ◽  
Nitrogen Vacancy ◽  
Quantum Network ◽  
Nuclear Spins ◽  
Nv Centers

Quantum computing and quantum communication have become the most popular research topic. Nitrogen-vacancy (NV) centers in diamond have been shown the great advantage of implementing quantum information processing. The generation of entanglement between NV centers represents a fundamental prerequisite for all quantum information technologies. In this paper, we propose a scheme to realize the high-fidelity storage and extraction of quantum entanglement information based on the NV centers at room temperature. We store the entangled information of a pair of entangled photons in the Bell state into the nuclear spins of two NV centers, which can make these two NV centers entangled. And then we illuminate how to extract the entangled information from NV centers to prepare on-demand entangled states for optical quantum information processing. The strategy of engineering entanglement demonstrated here maybe pave the way towards a NV center-based quantum network.

scholarly journals Algorithmic decomposition for efficient multiple nuclear spin detection in diamond

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Hyunseok Oh ◽  
Jiwon Yun ◽  
M. H. Abobeih ◽  
Kyung-Hoon Jung ◽  
Kiho Kim ◽  
...  
Keyword(s):  
Hyperfine Interaction ◽  
Nuclear Spin ◽  
Systematic Approach ◽  
Quantum Information Processing ◽  
Nitrogen Vacancy ◽  
Nuclear Spectroscopy ◽  
Nuclear Spins ◽  
Systematic Analysis ◽  
And Control ◽  
Spin Detection

Abstract Efficiently detecting and characterizing individual spins in solid-state hosts is an essential step to expand the fields of quantum sensing and quantum information processing. While selective detection and control of a few 13C nuclear spins in diamond have been demonstrated using the electron spin of nitrogen-vacancy (NV) centers, a reliable, efficient, and automatic characterization method is desired. Here, we develop an automated algorithmic method for decomposing spectral data to identify and characterize multiple nuclear spins in diamond. We demonstrate efficient nuclear spin identification and accurate reproduction of hyperfine interaction components for both virtual and experimental nuclear spectroscopy data. We conduct a systematic analysis of this methodology and discuss the range of hyperfine interaction components of each nuclear spin that the method can efficiently detect. The result demonstrates a systematic approach that automatically detects nuclear spins with the aid of computational methods, facilitating the future scalability of devices.

scholarly journals Quantum control in spintronics

2011 ◽  
Vol 369 (1948) ◽  
pp. 3229-3248 ◽  
Author(s):  
A. Ardavan ◽  
G. A. D. Briggs
Keyword(s):  
Quantum Control ◽  
Quantum Information Processing ◽  
Nitrogen Vacancy ◽  
Triplet States ◽  
Spin States ◽  
Electron Spins ◽  
Nuclear Spins ◽  
Holographic Storage ◽  
New Era ◽  
Quantum Phenomena

Superposition and entanglement are uniquely quantum phenomena. Superposition incorporates a phase that contains information surpassing any classical mixture. Entanglement offers correlations between measurements in quantum systems that are stronger than any that would be possible classically. These give quantum computing its spectacular potential, but the implications extend far beyond quantum information processing. Early applications may be found in entanglement-enhanced sensing and metrology. Quantum spins in condensed matter offer promising candidates for investigating and exploiting superposition and entanglement, and enormous progress is being made in quantum control of such systems. In gallium arsenide (GaAs), individual electron spins can be manipulated and measured, and singlet–triplet states can be controlled in double-dot structures. In silicon, individual electron spins can be detected by ionization of phosphorus donors, and information can be transferred from electron spins to nuclear spins to provide long memory times. Electron and nuclear spins can be manipulated in nitrogen atoms incarcerated in fullerene molecules, which in turn can be assembled in ordered arrays. Spin states of charged nitrogen vacancy centres in diamond can be manipulated and read optically. Collective spin states in a range of materials systems offer scope for holographic storage of information. Conditions are now excellent for implementing superposition and entanglement in spintronic devices, thereby opening up a new era of quantum technologies.

scholarly journals Deep learning enhanced individual nuclear-spin detection

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Kyunghoon Jung ◽  
M. H. Abobeih ◽  
Jiwon Yun ◽  
Gyeonghun Kim ◽  
Hyunseok Oh ◽  
...  
Keyword(s):  
Deep Learning ◽  
Nuclear Spin ◽  
Quantum Information Processing ◽  
Nuclear Interaction ◽  
Spin Systems ◽  
Nitrogen Vacancy ◽  
Atomic Scale ◽  
Automatic Identification ◽  
Nuclear Spins ◽  
Wide Range

AbstractThe detection of nuclear spins using individual electron spins has enabled diverse opportunities in quantum sensing and quantum information processing. Proof-of-principle experiments have demonstrated atomic-scale imaging of nuclear-spin samples and controlled multi-qubit registers. However, to image more complex samples and to realize larger-scale quantum processors, computerized methods that efficiently and automatically characterize spin systems are required. Here, we realize a deep learning model for automatic identification of nuclear spins using the electron spin of single nitrogen-vacancy (NV) centers in diamond as a sensor. Based on neural network algorithms, we develop noise recovery procedures and training sequences for highly non-linear spectra. We apply these methods to experimentally demonstrate the fast identification of 31 nuclear spins around a single NV center and accurately determine the hyperfine parameters. Our methods can be extended to larger spin systems and are applicable to a wide range of electron-nuclear interaction strengths. These results pave the way towards efficient imaging of complex spin samples and automatic characterization of large spin-qubit registers.

scholarly journals Gate fidelity and coherence of an electron spin in an Si/SiGe quantum dot with micromagnet

2016 ◽  
Vol 113 (42) ◽  
pp. 11738-11743 ◽  
Author(s):  
Erika Kawakami ◽  
Thibaut Jullien ◽  
Pasquale Scarlino ◽  
Daniel R. Ward ◽  
Donald E. Savage ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Electron Spin ◽  
Quantum Information Processing ◽  
Coherence Time ◽  
Nuclear Spins ◽  
Quantum Bit ◽  
Sige Quantum Dot ◽  
Qubit Gate ◽  
And Control ◽  
Charge Noise

The gate fidelity and the coherence time of a quantum bit (qubit) are important benchmarks for quantum computation. We construct a qubit using a single electron spin in an Si/SiGe quantum dot and control it electrically via an artificial spin-orbit field from a micromagnet. We measure an average single-qubit gate fidelity of ∼99% using randomized benchmarking, which is consistent with dephasing from the slowly evolving nuclear spins in the substrate. The coherence time measured using dynamical decoupling extends up to ∼400 μs for 128 decoupling pulses, with no sign of saturation. We find evidence that the coherence time is limited by noise in the 10-kHz to 1-MHz range, possibly because charge noise affects the spin via the micromagnet gradient. This work shows that an electron spin in an Si/SiGe quantum dot is a good candidate for quantum information processing as well as for a quantum memory, even without isotopic purification.

Quantum optics with nitrogen-vacancy centres in diamond

2017 ◽  
Author(s):  
Yiwen Chu ◽  
Mikhail D. Lukin
Keyword(s):  
Optical Properties ◽  
Quantum Information ◽  
Solid State ◽  
Quantum Optics ◽  
Quantum States ◽  
Nitrogen Vacancy ◽  
Common Theme ◽  
External Effects ◽  
Promising Candidate ◽  
Optical Photons

A common theme in the implementation of quantum technologies involves addressing the seemingly contradictory needs for controllability and isolation from external effects. Undesirable effects of the environment must be minimized, while at the same time techniques and tools must be developed that enable interaction with the system in a controllable and well-defined manner. This chapter addresses several aspects of this theme with regard to a particularly promising candidate for developing applications in both metrology and quantum information, namely the nitrogen-vacancy (NV) centre in diamond. The chapter describes how the quantum states of NV centres can be manipulated, probed, and efficiently coupled with optical photons. It also discusses ways of tackling the challenges of controlling the optical properties of these emitters inside a complex solid state environment.

scholarly journals Optical spin-state polarization in a binuclear europium complex towards molecule-based coherent light-spin interfaces

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Kuppusamy Senthil Kumar ◽  
Diana Serrano ◽  
Aline M. Nonat ◽  
Benoît Heinrich ◽  
Lydia Karmazin ◽  
...  
Keyword(s):  
Ground State ◽  
Quantum Information Processing ◽  
Optical Transition ◽  
Molecular Engineering ◽  
Coherent Light ◽  
Nuclear Spins ◽  
Rare Earth Ion ◽  
Molecular Systems ◽  
Homogeneous Linewidth ◽  
State Spin

AbstractThe success of the emerging field of solid-state optical quantum information processing (QIP) critically depends on the access to resonant optical materials. Rare-earth ion (REI)-based molecular systems, whose quantum properties could be tuned taking advantage of molecular engineering strategies, are one of the systems actively pursued for the implementation of QIP schemes. Herein, we demonstrate the efficient polarization of ground-state nuclear spins—a fundamental requirement for all-optical spin initialization and addressing—in a binuclear Eu(III) complex, featuring inhomogeneously broadened 5D0 → 7F0 optical transition. At 1.4 K, long-lived spectral holes have been burnt in the transition: homogeneous linewidth (Γh) = 22 ± 1 MHz, which translates as optical coherence lifetime (T2opt) = 14.5 ± 0.7 ns, and ground-state spin population lifetime (T1spin) = 1.6 ± 0.4 s have been obtained. The results presented in this study could be a progressive step towards the realization of molecule-based coherent light-spin QIP interfaces.

scholarly journals Room-temperature control and electrical readout of individual nitrogen-vacancy nuclear spins

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Michal Gulka ◽  
Daniel Wirtitsch ◽  
Viktor Ivády ◽  
Jelle Vodnik ◽  
Jaroslav Hruby ◽  
...  
Keyword(s):  
Dipolar Interaction ◽  
Coherence Time ◽  
Wide Bandgap ◽  
Nitrogen Vacancy ◽  
Ambient Conditions ◽  
Nuclear Spins ◽  
Quantum Device ◽  
Nanoscale Electronics ◽  
Quantum Processor ◽  
Processor Unit

AbstractNuclear spins in semiconductors are leading candidates for future quantum technologies, including quantum computation, communication, and sensing. Nuclear spins in diamond are particularly attractive due to their long coherence time. With the nitrogen-vacancy (NV) centre, such nuclear qubits benefit from an auxiliary electronic qubit, which, at cryogenic temperatures, enables probabilistic entanglement mediated optically by photonic links. Here, we demonstrate a concept of a microelectronic quantum device at ambient conditions using diamond as wide bandgap semiconductor. The basic quantum processor unit – a single 14N nuclear spin coupled to the NV electron – is read photoelectrically and thus operates in a manner compatible with nanoscale electronics. The underlying theory provides the key ingredients for photoelectric quantum gate operations and readout of nuclear qubit registers. This demonstration is, therefore, a step towards diamond quantum devices with a readout area limited by inter-electrode distance rather than by the diffraction limit. Such scalability could enable the development of electronic quantum processors based on the dipolar interaction of spin-qubits placed at nanoscopic proximity.

scholarly journals Generation and robustness of quantum entanglement in spin graphs

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Jan Riegelmeyer ◽  
Dan Wignall ◽  
Marta P. Estarellas ◽  
Irene D’Amico ◽  
Timothy P. Spiller
Keyword(s):  
Quantum Information Processing ◽  
Bell State ◽  
Spin Chains ◽  
Coupling Scheme ◽  
High Fidelity ◽  
Coupling Ratio ◽  
Entanglement Generation ◽  
Fabrication Errors ◽  
Coupling Strengths ◽  
Hardware Platforms

AbstractEntanglement is a crucial resource for quantum information processing, and so protocols to generate high-fidelity entangled states on various hardware platforms are in demand. While spin chains have been extensively studied to generate entanglement, graph structures also have such potential; however, only a few classes of graphs have been explored for this specific task. In this paper, we apply a particular coupling scheme involving two different coupling strengths to a graph of two interconnected $$3\times 3$$ 3 × 3 square graphs such that it effectively contains three defects. We show how this structure allows generation of a Bell state whose fidelity depends on the chosen coupling ratio. We apply partitioned graph theory in order to reduce the dimension of the graph and show that, using a reduced graph or a reduced chain, we can still simulate the same protocol with identical dynamics. Finally, we investigate how fabrication errors affect the entanglement generation protocol and how the different equivalent structures are affected, finding that for some specific coupling ratios they are extremely robust.

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