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Ronald L. Walsworth

Bio: Ronald L. Walsworth is an academic researcher from Harvard University. The author has contributed to research in topics: Diamond & Electromagnetically induced transparency. The author has an hindex of 75, co-authored 396 publications receiving 23031 citations. Previous affiliations of Ronald L. Walsworth include University of Michigan & Smithsonian Institution.


Papers
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Journal ArticleDOI
02 Oct 2008-Nature
TL;DR: An approach to nanoscale magnetic sensing is experimentally demonstrated, using coherent manipulation of an individual electronic spin qubit associated with a nitrogen-vacancy impurity in diamond at room temperature to achieve detection of 3 nT magnetic fields at kilohertz frequencies after 100 s of averaging.
Abstract: Detection of weak magnetic fields with nanoscale spatial resolution is an outstanding problem in the biological and physical sciences. For example, at a distance of 10 nm, the spin of a single electron produces a magnetic field of about 1 muT, and the corresponding field from a single proton is a few nanoteslas. A sensor able to detect such magnetic fields with nanometre spatial resolution would enable powerful applications, ranging from the detection of magnetic resonance signals from individual electron or nuclear spins in complex biological molecules to readout of classical or quantum bits of information encoded in an electron or nuclear spin memory. Here we experimentally demonstrate an approach to such nanoscale magnetic sensing, using coherent manipulation of an individual electronic spin qubit associated with a nitrogen-vacancy impurity in diamond at room temperature. Using an ultra-pure diamond sample, we achieve detection of 3 nT magnetic fields at kilohertz frequencies after 100 s of averaging. In addition, we demonstrate a sensitivity of 0.5 muT Hz(-1/2) for a diamond nanocrystal with a diameter of 30 nm.

1,817 citations

Journal ArticleDOI
TL;DR: In this paper, the use of diamond impurity centres as magnetic field sensors is explored, promising a new approach to single-spin detection and magnetic-field imaging at the nanoscale.
Abstract: Impurity centres in diamond have recently attracted attention in the context of quantum information processing. Now their use as magnetic-field sensors is explored, promising a fresh approach to single-spin detection and magnetic-field imaging at the nanoscale.

1,691 citations

Journal ArticleDOI
TL;DR: An experiment is reported in which a light pulse is effectively decelerated and trapped in a vapor of Rb atoms, stored for a controlled period of time, and then released on demand.
Abstract: We report an experiment in which a light pulse is effectively decelerated and trapped in a vapor of Rb atoms, stored for a controlled period of time, and then released on demand. We accomplish this ``storage of light'' by dynamically reducing the group velocity of the light pulse to zero, so that the coherent excitation of the light is reversibly mapped into a Zeeman (spin) coherence of the Rb vapor.

1,651 citations

Journal ArticleDOI
TL;DR: A robust method for scanning a single nitrogen-vacancy centre within tens of nanometres from a sample surface that addresses both of these concerns is demonstrated, and is able to image magnetic domains with widths of 25 nm, and demonstrate a magnetic field sensitivity of 56 nT Hz(-1/2) at a frequency of 33 kHz, which is unprecedented for scanning nitrogen-Vacancy centres.
Abstract: The nitrogen-vacancy defect centre in diamond has potential applications in nanoscale electric and magnetic-field sensing, single-photon microscopy, quantum information processing and bioimaging. These applications rely on the ability to position a single nitrogen-vacancy centre within a few nanometres of a sample, and then scan it across the sample surface, while preserving the centre's spin coherence and readout fidelity. However, existing scanning techniques, which use a single diamond nanocrystal grafted onto the tip of a scanning probe microscope, suffer from short spin coherence times due to poor crystal quality, and from inefficient far-field collection of the fluorescence from the nitrogen-vacancy centre. Here, we demonstrate a robust method for scanning a single nitrogen-vacancy centre within tens of nanometres from a sample surface that addresses both of these concerns. This is achieved by positioning a single nitrogen-vacancy centre at the end of a high-purity diamond nanopillar, which we use as the tip of an atomic force microscope. Our approach ensures long nitrogen-vacancy spin coherence times (∼75 µs), enhanced nitrogen-vacancy collection efficiencies due to waveguiding, and mechanical robustness of the device (several weeks of scanning time). We are able to image magnetic domains with widths of 25 nm, and demonstrate a magnetic field sensitivity of 56 nT Hz(-1/2) at a frequency of 33 kHz, which is unprecedented for scanning nitrogen-vacancy centres.

720 citations

Journal ArticleDOI
TL;DR: An improvement of more than two orders of magnitude is demonstrated in the spin coherence time of nitrogen-vacancy centres of diamond, which could advance quantum sensing, enable squeezing and many-body entanglement, and open a path to simulating driven, interaction-dominated quantum many- body Hamiltonians.
Abstract: Nitrogen-vacancy centres in diamond are a promising route for solid-state quantum information processing and magnetometry, but longer coherence times are needed to optimize protocols. Here, Bar-Gill et al. suppress decoherence to realize nitrogen-vacancy spin coherence times approaching one second.

717 citations


Cited by
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Journal ArticleDOI

[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

28 Jul 2005
TL;DR: PfPMP1)与感染红细胞、树突状组胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作�ly.
Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1(PfPMP1)与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员,通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

18,940 citations

Journal ArticleDOI
01 Apr 1988-Nature
TL;DR: In this paper, a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) is presented.
Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

9,929 citations