7,307 research outputs found

    The origin of the phase separation in partially deuterated κ\kappa-(ET)2_2Cu[N(CN)2_2]Br studied by infrared magneto-optical imaging spectroscopy

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    The direct observation of the phase separation between the metallic and insulating states of 75 %-deuterated κ\kappa-(ET)2_2Cu[N(CN)2_2]Br (d33d33) using infrared magneto-optical imaging spectroscopy is reported, as well as the associated temperature, cooling rate, and magnetic field dependencies of the separation. The distribution of the center of spectral weight () of d33d33 did not change under any of the conditions in which data were taken and was wider than that of the non-deuterated material. This result indicates that the inhomogenity of the sample itself is important as part of the origin of the metal - insulator phase separation.Comment: 4 pages, 3 figures, accepted for publication in Solid State Commu

    The segment as the minimal planning unit in speech production and reading aloud: evidence and implications.

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    Speech production and reading aloud studies have much in common, especially the last stages involved in producing a response. We focus on the minimal planning unit (MPU) in articulation. Although most researchers now assume that the MPU is the syllable, we argue that it is at least as small as the segment based on negative response latencies (i.e., response initiation before presentation of the complete target) and longer initial segment durations in a reading aloud task where the initial segment is primed. We also discuss why such evidence was not found in earlier studies. Next, we rebut arguments that the segment cannot be the MPU by appealing to flexible planning scope whereby planning units of different sizes can be used due to individual differences, as well as stimulus and experimental design differences. We also discuss why negative response latencies do not arise in some situations and why anticipatory coarticulation does not preclude the segment MPU. Finally, we argue that the segment MPU is also important because it provides an alternative explanation of results implicated in the serial vs. parallel processing debate

    Microscopic observation of superconducting fluctuations in κ\kappa-(BEDT-TTF)2_{2}Cu[N(CN)2_{2}]Br by 13^{13}C NMR spectroscopy

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    We performed 13^{13}C-NMR experiment and measured spin-lattice relaxation rate divided by temperature 1/T1T1/T_{1}T near the superconducting (SC) transition temperature TcT_{c} in κ\kappa-(BEDT-TTF)2_{2}Cu[N(CN)2_{2}]Br (κ\kappa-Br salt), and κ\kappa-(BEDT-TTF)2_{2}Cu(NCS)2_{2} (κ\kappa-NCS salt). We observed the reduction of 1/T1T1/T_{1}T starting at the temperature higher than TcT_c in κ\kappa-Br salt. Microscopic observation of quasi-particle density of states in the fluctuating SC state revealed the effects of short-range Cooper pairs induced in the normal state to the quasi-particle density of states. We also performed systematic measurements in the fields both parallel and perpendicular to the conduction plane in κ\kappa-Br and κ\kappa-NCS salts, and confirmed that the reduction of 1/T1T1/T_{1}T above TcT_{c} is observed only in κ\kappa-Br salt regardless of the external field orientation.Comment: Accepted for publication in PR

    The bosonic string and superstring models in 26+2 and 10+2 dimensional space--time, and the generalized Chern-Simons action

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    We have covariantized the Lagrangians of the U(1)_V * U(1)_A models, which have U(1)_V * U(1)_A gauge symmetry in two dimensions, and studied their symmetric structures. The special property of the U(1)_V * U(1)_A models is the fact that all these models have an extra time coordinate in the target space-time. The U(1)_V * U(1)_A models coupled to two-dimensional gravity are string models in 26+2 dimensional target space-time for bosonic string and in 10+2 dimensional target space-time for superstring. Both string models have two time coordinates. In order to construct the covariant Lagrangians of the U(1)_V * U(1)_A models the generalized Chern-Simons term plays an important role. The supersymmetric generalized Chern-Simons action is also proposed. The Green-Schwarz type of U(1)_V * U(1)_A superstring model has another fermionic local symmetry as well as \kappa-symmetry. The supersymmetry of target space-time is different from the standard one.Comment: 27 pages, no figure

    Structure of air shower disc near the core

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    The longitudinal structure of the air shower disk is studied by measuring the arrival time distributions of air shower particles for showers with electron size in the range 3.2 x 10 to the 5.5. power to 3.2 x 10 to the 7.5 power in the Akeno air-shower array (930 gcm squared atmospheric depth). The average FWHM as a parameter of thickness of air shower disk increases with core distances at less than 50m. AT the present stage, dependence on electron size, zenith angle and air shower age is not apparent. The average thickness of the air shower disk within a core distance of 50m could be determined by an electromagnetic cascade starting from the lower altitude

    Transfer Matrix Formalism for Two-Dimensional Quantum Gravity and Fractal Structures of Space-time

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    We develop a transfer matrix formalism for two-dimensional pure gravity. By taking the continuum limit, we obtain a "Hamiltonian formalism'' in which the geodesic distance plays the role of time. Applying this formalism, we obtain a universal function which describes the fractal structures of two dimensional quantum gravity in the continuum limit.Comment: 13 pages, 5 figures, phyzz