scholarly journals Photon-mediated interactions between quantum emitters in a diamond nanocavity

Science ◽  
2018 ◽  
Vol 362 (6415) ◽  
pp. 662-665 ◽  
Author(s):  
R. E. Evans ◽  
M. K. Bhaskar ◽  
D. D. Sukachev ◽  
C. T. Nguyen ◽  
A. Sipahigil ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Quantum Information Processing ◽  
Color Centers ◽  
Quantum Networks ◽  
Network Nodes ◽  
Electronic Spin ◽  
Coherent Interaction ◽  
The Common ◽  
Spectrally Resolved ◽  
Common Cavity

Photon-mediated interactions between quantum systems are essential for realizing quantum networks and scalable quantum information processing. We demonstrate such interactions between pairs of silicon-vacancy (SiV) color centers coupled to a diamond nanophotonic cavity. When the optical transitions of the two color centers are tuned into resonance, the coupling to the common cavity mode results in a coherent interaction between them, leading to spectrally resolved superradiant and subradiant states. We use the electronic spin degrees of freedom of the SiV centers to control these optically mediated interactions. Such controlled interactions will be crucial in developing cavity-mediated quantum gates between spin qubits and for realizing scalable quantum network nodes.

scholarly journals Hyperfine Interactions in the NV-13C Quantum Registers in Diamond Grown from the Azaadamantane Seed

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1303
Author(s):  
Alexander P. Nizovtsev ◽  
Aliaksandr L. Pushkarchuk ◽  
Sergei Ya. Kilin ◽  
Nikolai I. Kargin ◽  
Alexander S. Gusev ◽  
...  
Keyword(s):  
Organic Molecules ◽  
Quantum Information Processing ◽  
Hyperfine Interactions ◽  
Spin Systems ◽  
Diamond Growth ◽  
Color Centers ◽  
Nuclear Spins ◽  
Electronic Spin ◽  
Nv Center ◽  
Optically Detected

Nanostructured diamonds hosting optically active paramagnetic color centers (NV, SiV, GeV, etc.) and hyperfine-coupled with them quantum memory 13C nuclear spins situated in diamond lattice are currently of great interest to implement emerging quantum technologies (quantum information processing, quantum sensing and metrology). Current methods of creation such as electronic-nuclear spin systems are inherently probabilistic with respect to mutual location of color center electronic spin and 13C nuclear spins. A new bottom-up approach to fabricate such systems is to synthesize first chemically appropriate diamond-like organic molecules containing desired isotopic constituents in definite positions and then use them as a seed for diamond growth to produce macroscopic diamonds, subsequently creating vacancy-related color centers in them. In particular, diamonds incorporating coupled NV-13С spin systems (quantum registers) with specific mutual arrangements of NV and 13C can be obtained from anisotopic azaadamantane molecule. Here we predict the characteristics of hyperfine interactions (hfi) for the NV-13C systems in diamonds grown from various isotopically substituted azaadamantane molecules differing in 13C position in the seed, as well as the orientation of the NV center in the post-obtained diamond. We used the spatial and hfi data simulated earlier for the H-terminated cluster C510[NV]-H252. The data obtained can be used to identify (and correlate with the seed used) the specific NV-13C spin system by measuring, e.g., the hfi-induced splitting of the mS = ±1 sublevels of the NV center in optically detected magnetic resonance (ODMR) spectra being characteristic for various NV-13C systems.

scholarly journals Optomechanical interfaces for hybrid quantum networks

2015 ◽  
Vol 2 (4) ◽  
pp. 510-519 ◽  
Author(s):  
Chunhua Dong ◽  
Yingdan Wang ◽  
Hailin Wang
Keyword(s):  
Degrees Of Freedom ◽  
Quantum Communication ◽  
Quantum Information Processing ◽  
Quantum Systems ◽  
Optical Control ◽  
Special Role ◽  
Mechanical Motion ◽  
Optical Fields ◽  
Quantum Networks ◽  
Optical Resonances

Abstract Recent advances on optical control of mechanical motion in an optomechanical resonator have stimulated strong interests in exploring quantum behaviors of otherwise classical, macroscopic mechanical systems and especially in exploiting mechanical degrees of freedom for applications in quantum information processing. In an optomechanical resonator, an optically- active mechanical mode can couple to any of the optical resonances supported by the resonator via radiation pressure. This unique property leads to a remarkable phenomenon: mechanically-mediated conversion of optical fields between vastly different wavelengths. The resulting optomechanical interfaces can play a special role in a hybrid quantum network, enabling quantum communication between disparate quantum systems. In this review, we introduce the basic concepts of optomechanical interactions and discuss recent theoretical and experimental progresses in this field. A particular emphasis is on taking advantage of mechanical degrees of freedom, while avoiding detrimental effects of thermal mechanical motion.

scholarly journals Overlapping Community Discovery Method Based on Two Expansions of Seeds

Symmetry ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 18
Author(s):  
Yan Li ◽  
Jing He ◽  
Youxi Wu ◽  
Rongjie Lv
Keyword(s):  
Symmetric Matrix ◽  
Fitness Function ◽  
Local Maximum ◽  
Community Discovery ◽  
Network Nodes ◽  
Overlapping Community ◽  
The Common ◽  
New Research ◽  
Discovery Method ◽  
Discovery Algorithms

The real world can be characterized as a complex network sto in symmetric matrix. Community discovery (or community detection) can effectively reveal the common features of network groups. The communities are overlapping since, in fact, one thing often belongs to multiple categories. Hence, overlapping community discovery has become a new research hotspot. Since the results of the existing community discovery algorithms are not robust enough, this paper proposes an effective algorithm, named Two Expansions of Seeds (TES). TES adopts the topological feature of network nodes to find the local maximum nodes as the seeds which are based on the gravitational degree, which makes the community discovery robust. Then, the seeds are expanded by the greedy strategy based on the fitness function, and the community cleaning strategy is employed to avoid the nodes with negative fitness so as to improve the accuracy of community discovery. After that, the gravitational degree is used to expand the communities for the second time. Thus, all nodes in the network belong to at least one community. Finally, we calculate the distance between the communities and merge similar communities to obtain a less- undant community structure. Experimental results demonstrate that our algorithm outperforms other state-of-the-art algorithms.

3 Power and sample size for ABE in the 2× 2 design Here we give formulae for the calculation of the power of the TOST procedure assuming that there are in total n subjects in the 2× 2 trial. Suppose that the null hypotheses given below are to be tested using a 100(1 − α)% two-sided confidence interval and a power of (1 − β) is required to reject these hypotheses when they are false. H :µ ≤− ln 1.25 H :µ ≥ ln 1.25. Let us define x to be a random variable that has a noncentral t-distribution with df degrees of freedom and noncentrality parameter nc, i.e., x ∼ t(df,nc). The cumulative distribution function of x is defined as CDF(t,df,nc) = Pr(x≤ t). Assume that the power is to be calculated using log(AUC). If σ is the common within-subject variance for T and R for log(AUC), and n/2 subjects are allocated to each of the sequences RT and TR, then 1−β = CDF(t , df,nc )−CDF(t , df,nc ) (7.1) where √ n(log(µ )− log(0.8)) nc = 2σ √ n(log(µ )− log(1.25)) nc = 2σ √ (n− 2)(nc −nc = ) df 2t and t is the 100(1 − α)% point of the central t-distribution on n− 2 degrees of freedom. Some SAS code to calculate the power for an ABE 2 × 2 trial is given below, where the required input variables are α, σ value of the ratio µ and n, the total number of subjects in the trial.

2003 ◽  
pp. 361-361
Keyword(s):  
Distribution Function ◽  
Confidence Interval ◽  
Degrees Of Freedom ◽  
Random Variable ◽  
Noncentrality Parameter ◽  
Cumulative Distribution ◽  
Total N ◽  
The Common ◽  
Input Variables ◽  
T Distribution

An approach towards decentralized control of cooperating non-autonomous multiple robots

Robotica ◽  
2000 ◽  
Vol 18 (5) ◽  
pp. 495-504 ◽  
Author(s):  
Khalid Munawar ◽  
Masayoshi Esashi ◽  
Masaru Uchiyama
Keyword(s):  
Decentralized Control ◽  
Degrees Of Freedom ◽  
Real Life ◽  
Robotic Systems ◽  
Present System ◽  
Multiple Robots ◽  
Experimental Implementation ◽  
Control Scheme ◽  
The Common ◽  
Event Based

This paper introduces an event-based decentralized control scheme for the cooperation between multiple manipulators. This is in contrast to the common practice of using only centralized controls for such cooperation which, consequently, greatly limit the flexibility of robotic systems. The manipulators used in the present system are very simple with only two degrees of freedom, while even one of them is passive. Moreover these manipulators use very few and commonly available sensors only. Computer simulations indicated the applicability of the event-based decentralized control scheme for multi-manipulator cooperation, while real-life experimental implementation has proved that the proposed decentralized control scheme is fairly applicable for very simple and even under-actuated systems too. Hence, this work has opened new doors towards further research in this area. The proposed control scheme is expected to be equally applicable for any mobile or immobile multi-robotic system.

scholarly journals Quantum networks: topology and spectral characterization

2018 ◽  
Vol 182 ◽  
pp. 02014
Author(s):  
Vesna Berec
Keyword(s):  
Quantum Information Processing ◽  
Theoretic Approach ◽  
Quantum State Transfer ◽  
Complexity Measures ◽  
Quantum Networks ◽  
Graph Theoretic ◽  
Topological Features ◽  
State Transfer ◽  
Quantum Complexity ◽  
And Control

To utilize a scalable quantum network and perform a quantum state transfer within distant arbitrary nodes, coherence and control of the dynamics of couplings between the information units must be achieved as a prerequisite ingredient for quantum information processing within a hierarchical structure. Graph theoretic approach provides a powerful tool for the characterization of quantum networks with non-trivial clustering properties. By encoding the topological features of the underlying quantum graphs, relations between the quantum complexity measures are presented revealing the intricate links between a quantum and a classical networks dynamics.

Identification of Structural Systems With Limited Number of Sensors and Actuators

2004 ◽  
Author(s):  
Jun Yu ◽  
Maura Imbimbo ◽  
Raimondo Betti
Keyword(s):  
Degrees Of Freedom ◽  
Dynamic Models ◽  
Solution Space ◽  
Order Model ◽  
Sensors And Actuators ◽  
Common Assumption ◽  
Reduced Order ◽  
Different Types ◽  
The Common ◽  
Inverse Vibration

The common assumption in the so-called linear inverse vibration problem, which provides the mass/stiffness/damping matrices of second order dynamic models, is the availability of a full set of sensors and actuators. In “reduced-order” problems (with limited number of instrumentation), only the components of the eigenvector matrix regarding the measured degrees of freedom can be successfully identified while nothing can be said about the components connected to the unmeasured degrees of freedom. This paper presents a recently developed “reduced-order” model and expands such a model to a “full-order” one that is quite useful in damage detection. The five representative categories of “reduced-order” problems, defined by considering different types of geometrical conditions, are analyzed and a discussion on their solution space has been performed. The effectiveness and robustness of this approach is shown by means of a numerical example.

Analysis of Degree of Freedom of 4-SPxyzS/S Parallel Mechanism of the Imitation of Human Wrist

2014 ◽  
Vol 1006-1007 ◽  
pp. 654-657
Author(s):  
Ke Jiang Zang ◽  
Wan Shun Zang ◽  
Cai Hua Li ◽  
Xiao Ping Hu ◽  
Hai Xiang Wang
Keyword(s):  
Group Work ◽  
Traditional Method ◽  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Wrist Joint ◽  
Muscle Group ◽  
New Method ◽  
The Common ◽  
Theory Of Constraint ◽  
With Screws

The human wrist has three rotational DOFs. Elbow muscle group work together to drive the wrist joint. According to the above characteristics of human wrist, parallel mechanism with three rotational DOFs of the imitation of human wrist is built. Traditional method for calculating DOF based on arithmetic is not that accurate. The method for analysis of DOF based on theory of constraint screw is explained. According to theory of constraint screw, the parallel mechanism built was analyzed. All the kinematic pairs in the mechanism will be expressed with screws so that the common constraints and the over constraints will be obtained. Through analysis above, the DOFs of the mechanism can be calculated and which a few degrees of freedom of the mechanism will be known. The new method avoids the disadvantages of the traditional method.

scholarly journals Nonradiating and radiating modes excited by quantum emitters in open epsilon-near-zero cavities

2016 ◽  
Vol 2 (10) ◽  
pp. e1600987 ◽  
Author(s):  
Iñigo Liberal ◽  
Nader Engheta
Keyword(s):  
Degrees Of Freedom ◽  
Quantum Information Processing ◽  
State Of The Art ◽  
Optical Cavity ◽  
Dynamic Control ◽  
External Boundary ◽  
Dielectric Resonators ◽  
Optical Cavities ◽  
Epsilon Near Zero ◽  
Quantum Emitters

Controlling the emission and interaction properties of quantum emitters (QEs) embedded within an optical cavity is a key technique in engineering light-matter interactions at the nanoscale, as well as in the development of quantum information processing. State-of-the-art optical cavities are based on high quality factor photonic crystals and dielectric resonators. However, wealthier responses might be attainable with cavities carved in more exotic materials. We theoretically investigate the emission and interaction properties of QEs embedded in open epsilon-near-zero (ENZ) cavities. Using analytical methods and numerical simulations, we demonstrate that open ENZ cavities present the unique property of supporting nonradiating modes independently of the geometry of the external boundary of the cavity (shape, size, topology, etc.). Moreover, the possibility of switching between radiating and nonradiating modes enables a dynamic control of the emission by, and the interaction between, QEs. These phenomena provide unprecedented degrees of freedom in controlling and trapping fields within optical cavities, as well as in the design of cavity opto- and acoustomechanical systems.

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.

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