370 research outputs found
Implementation of a quantum controlled-SWAP gate with photonic circuits
Quantum information science addresses how the processing and transmission of
information are affected by uniquely quantum mechanical phenomena. Combination
of two-qubit gates has been used to realize quantum circuits, however,
scalability is becoming a critical problem. The use of three-qubit gates may
simplify the structure of quantum circuits dramatically. Among them, the
controlled-SWAP (Fredkin) gates are essential since they can be directly
applied to important protocols, e.g., error correction, fingerprinting, and
optimal cloning. Here we report a realization of the Fredkin gate for photonic
qubits. We achieve a fidelity of 0.85 in the computational basis and an output
state fidelity of 0.81 for a 3-photon Greenberger-Horne-Zeilinger state. The
estimated process fidelity of 0.77 indicates that our Fredkin gate can be
applied to various quantum tasks.Comment: 9 pages, 4 figures, Sci. Rep. 7, 45353 (2017
Tardigrades living on a sub-arctic glacier in Alaska
The Tenth Symposium on Polar Science/Ordinary sessions: [OB] Polar Biology, Wed. 4 Dec. / 3F Multipurpose conference room, National Institute of Polar Researc
Efficient decoherence-free entanglement distribution over lossy quantum channels
We propose and demonstrate a scheme for boosting up the efficiency of
entanglement distribution based on a decoherence-free subspace (DFS) over lossy
quantum channels. By using backward propagation of a coherent light, our scheme
achieves an entanglement-sharing rate that is proportional to the transmittance
T of the quantum channel in spite of encoding qubits in multipartite systems
for the DFS. We experimentally show that highly entangled states, which can
violate the Clauser-Horne-Shimony-Holt inequality, are distributed at a rate
proportional to T.Comment: 5pages, 5figure
Sexual dimorphism in body shape of Antarctic krill (Euphausia superba) and its influence on target strength
AbstractSexual dimorphism in the body shape of Antarctic krill (Euphausia superba) was investigated and its influence on target strength (TS) was clarified using a theoretical scattering model. The TS which is used to convert acoustic backscatter to krill density was also presented. Body shape data were obtained from 456 specimens (54 juveniles, 200 males, and 202 females) collected off Adélie Land using a Rectangular Midwater Trawl. The sexual dimorphism manifested as a swollen cephalothorax in female krill with body lengths exceeding 40 mm. The TS of female krill was higher than those of male krill at low frequencies, even when body lengths were the same. This is because of the Rayleigh scattering region and the transition region to the geometric scattering region. The influence of the sexual dimorphism on the TS was small at frequencies exceeding 70 kHz, which are close to the geometric scattering region. The regression curve derived from the predicted TS of 456 specimens was in reasonable agreement with the measured TS in other previous studies, and the regression curve could be applied to the acoustic surveys of Antarctic krill
Pan-Arctic Sea Ice Prediction System with the MIROC Climate Model
第6回極域科学シンポジウム分野横断セッション:[IA] 急変する北極気候システム及びその全球的な影響の総合的解明―GRENE北極気候変動研究事業研究成果報告2015―11月19日(木) 国立極地研究所1階交流アトリウ
Positive geographic correlation between soldiers’ weapon size and defensive prowess in a eusocial aphid, Ceratovacuna japonica
Some aphid species produce a soldier caste with enlarged forelegs and horns (weapons). It has been hypothesised that the evolution of morphological specialization by soldiers in social aphids is accelerated by high predation pressure, but this possibility has not been tested. Here, we investigated the relationship between local predator abundance and soldiers\u27 weapon size and aggressiveness in a prey-predator system comprising a eusocial aphid, Ceratovacuna japonica, and its predators (larvae of the butterfly Taraka hamada and of the moth Atkinsonia ignipicta) in two populations with different predator abundances. We found that the soldiers in the predator-abundant population had larger weapons and were more aggressive than those in the population with lower predator abundance. Furthermore, the soldiers\u27 defensive prowess (evaluated as the survival of aphids in the presence of predators) was greater in the predator-abundant population. These results provide the first evidence that a population of eusocial aphids experiencing high predation pressure has soldiers with pronounced defensive traits and defensive prowess
Electronic Structure and Electron Correlation in LaFeAsO_{1-x}F_x and LaFePO_{1-x}F_x
Photoemission spectroscopy is used to investigate the electronic structure of
the newly discovered iron-based superconductors LaFeAsO_{1-x}F_x and
LaFePO_{1-x}F_x. Line shapes of the Fe 2p core-level spectra suggest an
itinerant character of Fe 3d electrons. The valence-band spectra are generally
consistent with band-structure calculations except for the shifts of Fe
3d-derived peaks toward the Fermi level. From spectra taken in the Fe 3p -> 3d
core-absorption region, we have obtained the experimental Fe 3d partial density
of states, and explained it in terms of a band-structure calculation with a
phenomenological self-energy correction, yielding a mass renormalization factor
of ~< 2.Comment: 4 pages, 5 figure
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