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Journal ArticleDOI

A quantum memory intrinsic to single nitrogen-vacancy centres in diamond

01 Oct 2011-Nature Physics (Nature Publishing Group)-Vol. 7, Iss: 10, pp 789-793
TL;DR: In this paper, it was shown that the spin state of an electron localized to the nitrogen-vacancy centre can be transferred to the nuclear spin, where it can be stored until needed.
Abstract: A nitrogen impurity in diamond—where two of the carbon atoms are replaced by a nitrogen atom and a vacant lattice site—is seen as a valuable qubit. The spin of an electron localized to the nitrogen-vacancy centre is commonly used for processing. Researchers now show that this electron spin state can be transferred to the nitrogen nuclear spin, where it can be stored until needed.
Citations
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Journal ArticleDOI
TL;DR: Hybrid quantum circuits combine two or more physical systems, with the goal of harnessing the advantages and strengths of the different systems in order to better explore new phenomena and potentially bring about novel quantum technologies as discussed by the authors.
Abstract: Hybrid quantum circuits combine two or more physical systems, with the goal of harnessing the advantages and strengths of the different systems in order to better explore new phenomena and potentially bring about novel quantum technologies. This article presents a brief overview of the progress achieved so far in the field of hybrid circuits involving atoms, spins, and solid-state devices (including superconducting and nanomechanical systems). How these circuits combine elements from atomic physics, quantum optics, condensed matter physics, and nanoscience is discussed, and different possible approaches for integrating various systems into a single circuit are presented. In particular, hybrid quantum circuits can be fabricated on a chip, facilitating their future scalability, which is crucial for building future quantum technologies, including quantum detectors, simulators, and computers.

1,439 citations


Cites background or methods from "A quantum memory intrinsic to singl..."

  • ..., 2011), or transfers the quantum information from the electron spins to nearby nuclear spins by using the hyperfine interaction (Childress et al., 2006; Fuchs et al., 2011; Jiang et al., 2008)....

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  • ...…of laser pulses and microwave fields (de Lange et al., 2010; Fuchs et al., 2010; Naydenov et al., 2011), or transfers the quantum information from the electron spins to nearby nuclear spins by using the hyperfine interaction (Childress et al., 2006; Fuchs et al., 2011; Jiang et al., 2008)....

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Journal ArticleDOI
TL;DR: In this article, the authors review recent progress in impurity systems such as colour centres in diamond and silicon carbide, rare-earth ions in solids and donors in silicon and project a possible path to chip-scale quantum technologies through sustained advances in nanofabrication, quantum control and materials engineering.
Abstract: Spins of impurities in solids provide a unique architecture to realize quantum technologies. A quantum register of electron and nearby nuclear spins in the lattice encompasses high-fidelity state manipulation and readout, long-lived quantum memory, and long-distance transmission of quantum states by optical transitions that coherently connect spins and photons. These features, combined with solid-state device engineering, establish impurity spins as promising resources for quantum networks, information processing and sensing. Focusing on optical methods for the access and connectivity of single spins, we review recent progress in impurity systems such as colour centres in diamond and silicon carbide, rare-earth ions in solids and donors in silicon. We project a possible path to chip-scale quantum technologies through sustained advances in nanofabrication, quantum control and materials engineering.

696 citations

Journal ArticleDOI
08 Mar 2013-Science
TL;DR: The past decade has seen remarkable progress in isolating and controlling quantum coherence using charges and spins in semiconductors, and electron spin coherence times now exceed several seconds, a nine-fold increase in coherence compared with the first semiconductor qubits.
Abstract: The past decade has seen remarkable progress in isolating and controlling quantum coherence using charges and spins in semiconductors. Quantum control has been established at room temperature, and electron spin coherence times now exceed several seconds, a nine–order-of-magnitude increase in coherence compared with the first semiconductor qubits. These coherence times rival those traditionally found only in atomic systems, ushering in a new era of ultracoherent spintronics. We review recent advances in quantum measurements, coherent control, and the generation of entangled states and describe some of the challenges that remain for processing quantum information with spins in semiconductors.

691 citations

Journal ArticleDOI
TL;DR: In this article, the authors demonstrate entanglement between two engineered single solid-state spin quantum bits (qubits) at ambient conditions and show that ground-state quantum correlations can be detected by quantum state tomography.
Abstract: Entanglement is the central yet fleeting phenomenon of quantum physics. Once being considered a peculiar counter-intuitive property of quantum theory1, it has developed into the most central element of quantum technology. Consequently, there have been a number of experimental demonstrations of entanglement between photons2, atoms3, ions4 and solid-state systems such as spins or quantum dots5, 6, 7, superconducting circuits8, 9 and macroscopic diamond10. Here we experimentally demonstrate entanglement between two engineered single solid-state spin quantum bits (qubits) at ambient conditions. Photon emission of defect pairs reveals ground-state spin correlation. Entanglement (fidelity = 0.67±0.04) is proved by quantum state tomography. Moreover, the lifetime of electron spin entanglement is extended to milliseconds by entanglement swapping to nuclear spins. The experiments mark an important step towards a scalable room-temperature quantum device being of potential use in quantum information processing as well as metrology.

466 citations

Journal ArticleDOI
24 Jan 2013-Nature
TL;DR: The findings suggest the use of chemically amenable phenalenyl-based molecules as a viable and scalable platform for building molecular-scale quantum spin memory and processors for technological development.
Abstract: When molecules of a phenalenyl derivative, which has no net spin, are deposited on a ferromagnet, they develop into a magnetic supramolecular layer with spin-filtering properties; this could be the basis for a new approach to building molecular magnetic devices. Various types of molecular magnets carrying high localized spin have been studied as potential devices for information processing and storage, but it remains a considerable challenge to electronically couple to these spin centres. Moodera et al. have designed a phenalenyl derivative, essentially a graphene fragment, with the potential to act as an interface for the exchange of magnetic spin information in molecular spintronic devices. The graphene fragment has no net spin itself, but when deposited as a layer on a ferromagnet it transforms to produce a supramolecular magnetic film. The resulting nanoscale magnetic molecules, or memory 'bits', can be manipulated by external stimuli, and the resulting device exhibits an unexpectedly large magnetoresistance of 20% near room temperature. The use of molecular spin state as a quantum of information for storage, sensing and computing has generated considerable interest in the context of next-generation data storage and communication devices1,2, opening avenues for developing multifunctional molecular spintronics3. Such ideas have been researched extensively, using single-molecule magnets4,5 and molecules with a metal ion6 or nitrogen vacancy7 as localized spin-carrying centres for storage and for realizing logic operations8. However, the electronic coupling between the spin centres of these molecules is rather weak, which makes construction of quantum memory registers a challenging task9. In this regard, delocalized carbon-based radical species with unpaired spin, such as phenalenyl10, have shown promise. These phenalenyl moieties, which can be regarded as graphene fragments, are formed by the fusion of three benzene rings and belong to the class of open-shell systems. The spin structure of these molecules responds to external stimuli11,12 (such as light, and electric and magnetic fields), which provides novel schemes for performing spin memory and logic operations. Here we construct a molecular device using such molecules as templates to engineer interfacial spin transfer resulting from hybridization and magnetic exchange interaction with the surface of a ferromagnet; the device shows an unexpected interfacial magnetoresistance of more than 20 per cent near room temperature. Moreover, we successfully demonstrate the formation of a nanoscale magnetic molecule with a well-defined magnetic hysteresis on ferromagnetic surfaces. Owing to strong magnetic coupling with the ferromagnet, such independent switching of an adsorbed magnetic molecule has been unsuccessful with single-molecule magnets13. Our findings suggest the use of chemically amenable phenalenyl-based molecules as a viable and scalable platform for building molecular-scale quantum spin memory and processors for technological development.

373 citations

References
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Book
01 Jan 1973
TL;DR: CRC handbook of chemistry and physics, CRC Handbook of Chemistry and Physics, CRC handbook as discussed by the authors, CRC Handbook for Chemistry and Physiology, CRC Handbook for Physics,
Abstract: CRC handbook of chemistry and physics , CRC handbook of chemistry and physics , کتابخانه مرکزی دانشگاه علوم پزشکی تهران

52,268 citations

Book
01 Jan 2000
TL;DR: In this article, the quantum Fourier transform and its application in quantum information theory is discussed, and distance measures for quantum information are defined. And quantum error-correction and entropy and information are discussed.
Abstract: Part I Fundamental Concepts: 1 Introduction and overview 2 Introduction to quantum mechanics 3 Introduction to computer science Part II Quantum Computation: 4 Quantum circuits 5 The quantum Fourier transform and its application 6 Quantum search algorithms 7 Quantum computers: physical realization Part III Quantum Information: 8 Quantum noise and quantum operations 9 Distance measures for quantum information 10 Quantum error-correction 11 Entropy and information 12 Quantum information theory Appendices References Index

25,929 citations

01 Dec 2010
TL;DR: This chapter discusses quantum information theory, public-key cryptography and the RSA cryptosystem, and the proof of Lieb's theorem.
Abstract: Part I. Fundamental Concepts: 1. Introduction and overview 2. Introduction to quantum mechanics 3. Introduction to computer science Part II. Quantum Computation: 4. Quantum circuits 5. The quantum Fourier transform and its application 6. Quantum search algorithms 7. Quantum computers: physical realization Part III. Quantum Information: 8. Quantum noise and quantum operations 9. Distance measures for quantum information 10. Quantum error-correction 11. Entropy and information 12. Quantum information theory Appendices References Index.

14,825 citations


Additional excerpts

  • ...dtd" [ ]> The development of scalable memory elements is a critical step toward realizing large-scale quantum technolog...

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01 Jan 1992

12,636 citations

Journal ArticleDOI
TL;DR: In this paper, the crossing of a polar and homopolar state of a molecule with stationary nuclei has been studied, and the essential features may be illustrated in the crossing.
Abstract: The crossing of energy levels has been a matter of considerable discussion. The essential features may be illustrated in the crossing of a polar and homopolar state of a molecule. Let ψ1 ( x /R), ψ2 ( x /R) be two electronic eigenfunctions of a molecule with stationary nuclei. Let these eigenfunctions have the property that for R≫R, ψ1 has polar characteristics, ψ2 homopolar; while at R≪R, ψ2 has polar characteristics, ψ1 homopolar. In the region R=R these two eigenfunctions may be said to exchange their characteristics.

3,509 citations

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