18,503 research outputs found
Storage and Retrieval of Thermal Light in Warm Atomic Vapor
We report slowed propagation and storage and retrieval of thermal light in
warm rubidium vapor using the effect of electromagnetically-induced
transparency (EIT). We first demonstrate slowed-propagation of the probe
thermal light beam through an EIT medium by measuring the second-order
correlation function of the light field using the Hanbury-BrownTwiss
interferometer. We also report an experimental study on the effect of the EIT
slow-light medium on the temporal coherence of thermal light. Finally, we
demonstrate the storage and retrieval of thermal light beam in the EIT medium.
The direct measurement of the photon number statistics of the retrieved light
field shows that the photon number statistics is preserved during the storage
and retrieval process.Comment: 4 pages, 4 figure
Macroscopic Many-Qubit Interactions in Superconducting Flux Qubits
Superconducting flux qubits are considered to investigate macroscopic
many-qubit interactions.
Many-qubit states based on current states can be manipulated through the
current-phase relation in each superconducting loop.
For flux qubit systems comprised of qubit loops, a general expression of
low energy Hamiltonian is presented in terms of low energy levels of qubits and
macroscopic quantum tunnelings between the many-qubit states.
Many-qubit interactions classified by {\em Ising type- or tunnel-}exchange
interactions can be observable experimentally.
Flux qubit systems can provide various artificial-spin systems to study
many-body systems that cannot be found naturally.Comment: 5 pages, 1 figur
Reversing the Weak Quantum Measurement for a Photonic Qubit
We demonstrate the conditional reversal of a weak (partial-collapse) quantum
measurement on a photonic qubit. The weak quantum measurement causes a
nonunitary transformation of a qubit which is subsequently reversed to the
original state after a successful reversing operation. Both the weak
measurement and the reversal operation are implemented linear optically. The
state recovery fidelity, determined by quantum process tomography, is shown to
be over 94% for partial-collapse strength up to 0.9. We also experimentally
study information gain due to the weak measurement and discuss the role of the
reversing operation as an information erasure
On Electrical Equivalence of Aperture-Body and Transmission-Cavity Resonance Phenomena in Subwavelength Conducting Aperture Systems from an Equivalent Circuit Point of View
For a narrow slit structure backed by a conducting strip which is taken as a
representative example of an aperture-body resonance (ABR) problem, the
transmission resonance condition (i.e., condition for maximum power
transmission) and the transmission width (i.e., normalized maximum transmitted
power through the slit) are found to be the same as those for narrow slit
coupling problem in a thick conducting screen, which is designated as a
transmission-cavity resonance (TCR) problem. From a viewpoint of equivalent
circuit representation for the transmission resonance condition and the
funneling mechanism, the ABR and the TCR problems are thought to be essentially
of the same nature.Comment: 14 pages, 3 figure
Quartet consistency count method for reconstructing phylogenetic trees
Among the distance based algorithms in phylogenetic tree reconstruction, the
neighbor-joining algorithm has been a widely used and effective method. We
propose a new algorithm which counts the number of consistent quartets for
cherry picking with tie breaking. We show that the success rate of the new
algorithm is almost equal to that of neighbor-joining. This gives an
explanation of the qualitative nature of neighbor-joining and that of
dissimilarity maps from DNA sequence data. Moreover, the new algorithm always
reconstructs correct trees from quartet consistent dissimilarity maps.Comment: 11 pages, 5 figure
Online home appliance control using EEG-Based brain-computer interfaces
Brain???computer interfaces (BCIs) allow patients with paralysis to control external devices by mental commands. Recent advances in home automation and the Internet of things may extend the horizon of BCI applications into daily living environments at home. In this study, we developed an online BCI based on scalp electroencephalography (EEG) to control home appliances. The BCI users controlled TV channels, a digital door-lock system, and an electric light system in an unshielded environment. The BCI was designed to harness P300 andN200 components of event-related potentials (ERPs). On average, the BCI users could control TV channels with an accuracy of 83.0% ?? 17.9%, the digital door-lock with 78.7% ?? 16.2% accuracy, and the light with 80.0% ?? 15.6% accuracy, respectively. Our study demonstrates a feasibility to control multiple home appliances using EEG-based BCIs
Distinctive-attribute Extraction for Image Captioning
Image captioning, an open research issue, has been evolved with the progress
of deep neural networks. Convolutional neural networks (CNNs) and recurrent
neural networks (RNNs) are employed to compute image features and generate
natural language descriptions in the research. In previous works, a caption
involving semantic description can be generated by applying additional
information into the RNNs. In this approach, we propose a distinctive-attribute
extraction (DaE) which explicitly encourages significant meanings to generate
an accurate caption describing the overall meaning of the image with their
unique situation. Specifically, the captions of training images are analyzed by
term frequency-inverse document frequency (TF-IDF), and the analyzed semantic
information is trained to extract distinctive-attributes for inferring
captions. The proposed scheme is evaluated on a challenge data, and it improves
an objective performance while describing images in more detail.Comment: 14 main pages, 4 supplementary page
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