872 research outputs found

    Propagation of singularities for Schr\"odinger equations with modestly long range type potentials

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    In a previous paper by the second author, we discussed a characterization of the microlocal singularities for solutions to Schr\"odinger equations with long range type perturbations, using solutions to a Hamilton-Jacobi equation. In this paper we show that we may use Dollard type approximate solutions to the Hamilton-Jacobi equation if the perturbation satisfies somewhat stronger conditions. As applications, we describe the propagation of microlocal singularities for eitH0eitHe^{itH_0}e^{-itH} when the potential is asymptotically homogeneous as x|x|\to\infty, where HH is our Schr\"odinger operator, and H0H_0 is the free Schr\"odinger operator, i.e., H0=12H_0=-\frac12 \triangle. We show eitH0eitHe^{itH_0}e^{-itH} shifts the wave front set if the potential VV is asymptotically homogeneous of order 1, whereas eitHeitH0e^{itH}e^{-itH_0} is smoothing if VV is asymptotically homogenous of order β(1,3/2)\beta\in (1,3/2)

    Deterministic photon-photon (SWAP)^{1/2} gate using a lambda system

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    We theoretically present a method to realize a deterministic photon-photon (SWAP)^{1/2} gate using a three-level lambda system interacting with single photons in reflection geometry. The lambda system is used completely passively as a temporary memory for a photonic qubit; the initial state of the lambda system may be arbitrary, and active control by auxiliary fields is unnecessary throughout the gate operations. These distinct merits make this entangling gate suitable for deterministic and scalable quantum computation.Comment: 7 pages, 4 figure

    階層ベイズモデルを利用した実行可能な健康改善プランを提案するAI技術の開発

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    京都大学新制・課程博士博士(人間健康科学)甲第24539号人健博第110号新制||人健||8(附属図書館)京都大学大学院医学研究科人間健康科学系専攻(主査)教授 木下 彩栄, 教授 中尾 恵, 教授 中山 健夫学位規則第4条第1項該当Doctor of Human Health SciencesKyoto UniversityDFA

    Application of Quantum Annealing to Nurse Scheduling Problem

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    Quantum annealing is a promising heuristic method to solve combinatorial optimization problems, and efforts to quantify performance on real-world problems provide insights into how this approach may be best used in practice. We investigate the empirical performance of quantum annealing to solve the Nurse Scheduling Problem (NSP) with hard constraints using the D-Wave 2000Q quantum annealing device. NSP seeks the optimal assignment for a set of nurses to shifts under an accompanying set of constraints on schedule and personnel. After reducing NSP to a novel Ising-type Hamiltonian, we evaluate the solution quality obtained from the D-Wave 2000Q against the constraint requirements as well as the diversity of solutions. For the test problems explored here, our results indicate that quantum annealing recovers satisfying solutions for NSP and suggests the heuristic method is sufficient for practical use. Moreover, we observe that solution quality can be greatly improved through the use of reverse annealing, in which it is possible to refine a returned results by using the annealing process a second time. We compare the performance NSP using both forward and reverse annealing methods and describe how these approach might be used in practice.Comment: 20 pages, 13 figure

    Anticancer and antimetastatic effects of cordycepin, an active component of Cordyceps sinensis

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    AbstractCordyceps sinensis, a fungus that parasitizes on the larva of Lepidoptera, has been used as a valued traditional Chinese medicine. We investigated the effects of water extracts of Cordyceps sinensis (WECS), and particularly focused on its anticancer and antimetastatic actions. Based on in vitro studies, we report that WECS showed an anticancer action, and this action was antagonized by an adenosine A3 receptor antagonist. Moreover, this anticancer action of WECS was promoted by an adenosine deaminase inhibitor. These results suggest that one of the components of WECS with an anticancer action might be an adenosine or its derivatives. Therefore, we focused on cordycepin (3′-deoxyadenosine) as one of the active ingredients of WECS. According to our experiments, cordycepin showed an anticancer effect through the stimulation of adenosine A3 receptor, followed by glycogen synthase kinase (GSK)-3β activation and cyclin D1 suppression. Cordycepin also showed an antimetastatic action through inhibiting platelet aggregation induced by cancer cells and suppressing the invasiveness of cancer cells via inhibiting the activity of matrix metalloproteinase (MMP)-2 and MMP-9, and accelerating the secretion of tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 from cancer cells. In conclusion, cordycepin, an active component of WECS, might be a candidate anticancer and antimetastatic agent

    Broadband coherent Raman scattering spectroscopy at 50,000,000 spectra/s

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    Raman scattering spectroscopy is widely used as an analytical technique in various fields, but its measurement process tends to be slow due to the low scattering cross-section. In the last decade, various broadband coherent Raman scattering spectroscopy techniques have been developed to address this limitation, achieving a measurement rate of about 100 kSpectra/s. Here, we present a significantly increased measurement rate of 50 MSpectra/s, which is 500 times higher than the previous state-of-the-art, by developing time-stretch coherent Raman scattering spectroscopy. Our newly-developed system, based on a mode-locked Yb fiber laser, enables highly-efficient broadband excitation of molecular vibrations via impulsive stimulated Raman scattering with an ultrashort femtosecond pulse and sensitive time-stretch detection with a picosecond probe pulse at a high repetition rate of the laser. As a proof-of-concept demonstration, we measure broadband coherent Stokes Raman scattering spectra of organic compounds covering the molecular fingerprint region from 200 to 1,200 cm-1. This high-speed broadband vibrational spectroscopy technique holds promise for unprecedented measurements of sub-microsecond dynamics of irreversible phenomena and extremely high-throughput measurements
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