7,382 research outputs found
Coherent output of photons from coupled superconducting transmission line resonators controlled by charge qubits
We study the coherent control of microwave photons propagating in a
superconducting waveguide consisting of coupled transmission line resonators,
each of which is connected to a tunable charge qubit. While these coupled line
resonators form an artificial photonic crystal with an engineered photonic band
structure, the charge qubits collectively behave as spin waves in the low
excitation limit, which modify the band-gap structure to slow and stop the
microwave propagation. The conceptual exploration here suggests an
electromagnetically controlled quantum device based on the on-chip circuit QED
for the coherent manipulation of photons, such as the dynamic creation of
laser-like output from the waveguide by pumping the artificial atoms for
population inversion.Comment: 8 pages, 3 figure
Efficient single-photon-assisted entanglement concentration for partially entangled photon pairs
We present two realistic entanglement concentration protocols (ECPs) for pure
partially entangled photons. A partially entangled photon pair can be
concentrated to a maximally entangled pair with only an ancillary single photon
in a certain probability, while the conventional ones require two copies of
partially entangled pairs at least. Our first protocol is implemented with
linear optics and the second one is implemented with cross-Kerr nonlinearities.
Compared with other ECPs, they do not need to know the accurate coefficients of
the initial state. With linear optics, it is feasible with current experiment.
With cross-Kerr nonlinearities, it does not require the sophisticated
single-photon detectors and can be repeated to get a higher success
probability. Moreover, the second protocol can get the higher entanglement
transformation efficiency and it maybe the most economical one by far.
Meanwhile, both of protocols are more suitable for multi-photon system
concentration, because they need less operations and classical communications.
All these advantages make two protocols be useful in current long-distance
quantum communications
Prospects for Higgs Searches via VBF at the LHC with the ATLAS Detector
We report on the potential for the discovery of a Standard Model Higgs boson
with the vector boson fusion mechanism in the mass range 115
with the ATLAS experiment at the LHC. Feasibility studies at hadron level
followed by a fast detector simulation have been performed for H\to
W^{(*)}W^{(*)}\to l^+l^-\sla{p_T}, and . The results obtained show a large discovery potential in the
range 115. Results obtained with multivariate techniques are
reported for a number of channels.Comment: 14 pages, 4 figures, contributed to 2003 Les Houches Workshop on
Physics at TeV Colliders. Incorporated comments from ATLAS referee
Normalizing Weak Boson Pair Production at the Large Hadron Collider
The production of two weak bosons at the Large Hadron Collider will be one of
the most important sources of SM backgrounds for final states with multiple
leptons. In this paper we consider several quantities that can help normalize
the production of weak boson pairs. Ratios of inclusive cross-sections for
production of two weak bosons and Drell-Yan are investigated and the
corresponding theoretical errors are evaluated. The possibility of predicting
the jet veto survival probability of VV production from Drell-Yan data is also
considered. Overall, the theoretical errors on all quantities remain less than
5-20%. The dependence of these quantities on the center of mass energy of the
proton-proton collision is also studied.Comment: 11 pages; added references, minor text revisions, version to appear
in Phys. Rev.
Chemistry of fuel deposits and sediments and their predursors
The mechanism of solid deposit formation on hot engine parts from turbine fuels is investigated. Deposit formation is associated with oxidation of the hydrocarbon fuel. Therefore, oxidation rates and soluble gum formation were measured for several jet turbine fuels and pure hydrocarbon mixtures. Experiments were performed at 130 C using thermal initiation and at 100 C using ditertiary butyl peroxide as a chemical initiator. Correlation of the data shows that the ratio of rate of oxidation to rate of gum formation for a single fuel is not much affected by experimental conditions, even though there are differences in the abilities of different hydrocarbons to initiate and continue the oxidation. This indicates a close association of gum formation with the oxidation process. Oxidations of n-dodecane, tetralin and the more unstable jet fuels are autocatalytic, while those of 2-ethylnaphthalene and a stable jet fuel are self-retarding. However, the ratio of oxidation rate to gum formation rate appear to be nearly constant for each substrate. The effect of oxygen pressure on gum and oxidation formation was also studied. Dependence of gum formation on the concentration of initiator at 100 C is discussed and problems for future study are suggested
Efficient two-step entanglement concentration for arbitrary W states
We present two two-step practical entanglement concentration protocols (ECPs)
for concentrating an arbitrary three-particle less-entangled W state into a
maximally entangled W state assisted with single photons. The first protocol
uses the linear optics and the second protocol adopts the cross-Kerr
nonlinearity to perform the protocol. In the first protocol, based on the
post-selection principle, three parties say Alice, Bob and Charlie in different
distant locations can obtain the maximally entangled W state from the arbitrary
less-entangled W state with a certain success probability. In the second
protocol, it dose not require the parties to posses the sophisticated
single-photon detectors and the concentrated photon pair can be retained after
performing this protocol successfully. Moreover, the second protocol can be
repeated to get a higher success probability. Both protocols may be useful in
practical quantum information applications.Comment: 10 pages, 4 figure
Blunt-end vectors generated by polymerase chain reaction (PCR) for direct cloning of blunt-end DNA fragments
Blunt-end cloning is a convenient way to clone polymerase chain reaction (PCR) products generated by proof-reading DNA polymerase. However, it is a time consuming procedure to prepare the linearized blunt-end vector, which usually involves plasmid extraction and restriction enzyme digestion. Moreover, 5’ dephosporylation of the vector is usually required to avoid vector self-ligation. Here, we reported a method for generating linearized blunt-end vector pBSK-blunt by PCR. Vector generated in this way has no 5’-phosphate groups, hence completely avoiding vector self-ligation and yielding almost 100% positive clones.Key words: Blunt-end cloning, phosphorylated DNA fragment, dephosphorylated blunt-end vector
Predicting Future Instance Segmentation by Forecasting Convolutional Features
Anticipating future events is an important prerequisite towards intelligent
behavior. Video forecasting has been studied as a proxy task towards this goal.
Recent work has shown that to predict semantic segmentation of future frames,
forecasting at the semantic level is more effective than forecasting RGB frames
and then segmenting these. In this paper we consider the more challenging
problem of future instance segmentation, which additionally segments out
individual objects. To deal with a varying number of output labels per image,
we develop a predictive model in the space of fixed-sized convolutional
features of the Mask R-CNN instance segmentation model. We apply the "detection
head'" of Mask R-CNN on the predicted features to produce the instance
segmentation of future frames. Experiments show that this approach
significantly improves over strong baselines based on optical flow and
repurposed instance segmentation architectures
Current status and future trends of precision agricultural aviation technologies
Modern technologies and information tools can be used to maximize agricultural aviation productivity allowing for precision application of agrochemical products. This paper reviews and summarizes the state-of-the-art in precision agricultural aviation technology highlighting remote sensing, aerial spraying and ground verification technologies. Further, the authors forecast the future of precision agricultural aviation technology with key development directions in precision agricultural aviation technologies, such as real-time image processing, variable-rate spraying, multi-sensor data fusion and RTK differential positioning, and other supporting technologies for UAV-based aerial spraying. This review is expected to provide references for peers by summarizing the history and achievements, and encourage further development of precision agricultural aviation technologies
Quantitative characterisation of the layered structure within lithium-ion batteries using ultrasonic resonance
Lithium-ion batteries (LIBs) are becoming an important energy storage solution to achieve carbon neutrality, but it remains challenging to characterise their internal states for the assurance of performance, durability and safety. This work reports a simple but powerful non-destructive characterisation technique, based on the formation of ultrasonic resonance from the repetitive layers within LIBs. A physical model is developed from the ground up, to interpret the results from standard experimental ultrasonic measurement setups. As output, the method delivers a range of critical pieces of information about the inner structure of LIBs, such as the number of layers, the average thicknesses of electrodes, the image of internal layers, and the states of charge variations across individual layers. This enables the quantitative tracking of internal cell properties, potentially providing new means of quality control during production processes, and tracking the states of health and charge during operation
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