1,452 research outputs found

    Emergent Supersymmetry in Warped Backgrounds

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    We show that quantum mechanical supersymmetries are emerged in Kaluza-Klein spectrum of linearized gravity in several warped backgrounds as a consequence of higher-dimensional general coordinate invariance. These emergent supersymmetries play an essential role for the spectral structure of braneworld gravity. We show that for the case of braneworld models with two codimension-1 branes the spectral pattern is completely determined only through the supersymmetries

    Running Boundary Condition

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    In this paper we argue that boundary condition may run with energy scale. As an illustrative example, we consider one-dimensional quantum mechanics for a spinless particle that freely propagates in the bulk yet interacts only at the origin. In this setting we find the renormalization group flow of U(2) family of boundary conditions exactly. We show that the well-known scale-independent subfamily of boundary conditions are realized as fixed points. We also discuss the duality between two distinct boundary conditions from the renormalization group point of view. Generalizations to conformal mechanics and quantum graph are also discussed.Comment: PTPTeX, 21 pages, 8 eps figures; typos corrected, references and an appendix adde

    Dependence of sensitizer concentration on grain size in sulfur sensitized emulsion

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    A series of emulsions (fine, medium and coarse) was precipitated by double jet addition. The surface area of each emulsion was determined by adsorption of l,l\u27-diethyl-2,2’-cyanine in varying amounts and measurement of spectral reflectance, and the electron micrograph of each emulsion was taken. The emulsions were sensitized with differing concentrations of thiosulfate sensitizer and for various digestion time. The relationships between grain surface, grain size, and sensitizer concentration were determined by combining the optimum results of three individual experiments. From the sensitometric properties, the relation between grain size and optimum concentration of sensitizer was determined. Also the relationships between grain size and maximum sensitivity, and between fog and optimum speed were determined. The results showed that the rate of growth of sensitivity and fog increased with increasing thiosulfate concentration and grain size, and the optimum sensitizer concentration was independent of grain size. Also it was indicated that fog began to rise when the optimum speed was reached

    Gauge-Fixing and Residual Symmetries in Gauge/Gravity Theories with Extra Dimensions

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    We study compactified pure gauge/gravitational theories with gauge-fixing terms and show that these theories possess quantum mechanical SUSY-like symmetries between unphysical degrees of freedom. These residual symmetries are global symmetries and generated by quantum mechanical N=2 supercharges. Also, we establish new one-parameter family of gauge choices for higher-dimensional gravity, and calculate as a check of its validity one graviton exchange amplitude in the lowest tree-level approximation. We confirm that the result is indeed ξ\xi-independent and the cancellation of the ξ\xi-dependence is ensured by the residual symmetries. We also give a simple interpretation of the vDVZ-discontinuity, which arises in the lowest tree-level approximation, from the supersymmetric point of view.Comment: REVTeX4, 17 pages, 1 figur

    Phase Structure of Gauge Theories on an Interval

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    We discuss gauge symmetry breaking in a general framework of gauge theories on an interval. We first derive a possible set of boundary conditions for a scalar field, which are compatible with several consistency requirements. It is shown that with these boundary conditions the scalar field can acquire a nontrivial vacuum expectation value even if the scalar mass square is positive. Any nonvanishing vacuum expectation value cannot be a constant but, in general, depends on the extra dimensional coordinate of the interval. The phase diagram of broken/unbroken gauge symmetry possesses a rich structure in the parameter space of the length of the interval, the scalar mass and the boundary conditions. We also discuss 4d chiral fermions and fermion mass hierarchies in our gauge symmetry breaking scenario.Comment: 16 pages, 8 figure

    Noncontact measurement of heartbeat of humans and chimpanzees using millimeter-wave radar with topology method

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    チンパンジーの瞬時心拍間隔を非接触で測定することに成功 --ミリ波レーダを用いた非接触バイタル測定技術の確立へ--. 京都大学プレスリリース. 2023-10-18.This study proposes a method to determine the filter parameters required for the topology method, which is a radar-based noncontact method for measurement of heart inter-beat intervals. The effectiveness of the proposed method is evaluated by performing radar measurements involving both human participants and chimpanzee subjects. The proposed method is designed to enable setting of the filter cutoff frequency to eliminate respiratory components while maintaining the higher harmonics of the heartbeat components. Measurements using a millimeter-wave radar system and a reference contact -type electrocardiogram sensor demonstrate that the smallest errors that occur when measuring heart inter-beat intervals using the proposed method can be as small as 4.43 and 2.55 ms for humans and chimpanzees, respectively. These results indicate the possibility of using noncontact physiological measurements to monitor both humans and chimpanzees
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