85,601 research outputs found

    Reworking the Tucson-Melbourne Three-Nucleon Potential

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    We introduce new values of the strength constants (i.e., aa, bb, cc, and dd coefficients) of the Tucson-Melbourne (TM) 2π\pi exchange three nucleon potential. The new values come from contemporary dispersion relation analyses of meson factory π\piN scattering data. We make variational Monte Carlo calculations of the triton with the original and updated three-body forces to study the effects of this update. We remove a short-range -- π\pi-range part of the potential due to the cc coefficient and discuss the effect on the triton binding energy.Comment: 12 pages, to appear in Few-Body System

    The effect of asymmetry of the coil block on self-assembly in ABC coil-rod-coil triblock copolymers

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    Using the self-consistent field approach, the effect of asymmetry of the coil block on the microphase separation is focused in ABC coil-rod-coil triblock copolymers. For different fractions of the rod block fBf_{\text B}, some stable structures are observed, i.e., lamellae, cylinders, gyroid, and core-shell hexagonal lattice, and the phase diagrams are constructed. The calculated results show that the effect of the coil block fraction fAf_{\text A} is dependent on fBf_{\text B}. When fB=0.2f_{\text B}=0.2, the effect of asymmetry of the coil block is similar to that of the ABC flexible triblock copolymers; When fB=0.4f_{\text B}=0.4, the self-assembly of ABC coil-rod-coil triblock copolymers behaves like rod-coil diblock copolymers under some condition. When fBf_{\text B} continues to increase, the effect of asymmetry of the coil block reduces. For fB=0.4f_{\text B}=0.4, under the symmetrical and rather asymmetrical conditions, an increase in the interaction parameter between different components leads to different transitions between cylinders and lamellae. The results indicate some remarkable effect of the chain architecture on self-assembly, and can provide the guidance for the design and synthesis of copolymer materials.Comment: 9 pages, 3 figure

    Violation of Kohler's rule by the magnetoresistance of a quasi-two-dimensional organic metal

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    The interlayer magnetoresistance of the quasi-two-dimensional metal α\alpha-(BEDT-TTF)2_2KHg(SCN)4_4 is considered. In the temperature range from 0.5 to 10 K and for fields up to 10 tesla the magnetoresistance has a stronger temperature dependence than the zero-field resistance. Consequently Kohler's rule is not obeyed for any range of temperatures or fields. This means that the magnetoresistance cannot be described in terms of semiclassical transport on a single Fermi surface with a single scattering time. Possible explanations for the violations of Kohler's rule are considered, both within the framework of semi-classical transport theory and involving incoherent interlayer transport. The issues considered are similar to those raised by the magnetotransport of the cuprate superconductors.Comment: 5 pages, RevTeX + epsf, 2 figures. Slightly revised version to appear in Physical Review B, May 15, 199

    Effect of polymer concentration and length of hydrophobic end block on the unimer-micelle transition broadness in amphiphilic ABA symmetric triblock copolymer solutions

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    The effects of the length of each hydrophobic end block N_{st} and polymer concentration \bar{\phi}_{P} on the transition broadness in amphiphilic ABA symmetric triblock copolymer solutions are studied using the self-consistent field lattice model. When the system is cooled, micelles are observed, i.e.,the homogenous solution (unimer)-micelle transition occurs. When N_{st} is increased, at fixed \bar{\phi}_{P}, micelles occur at higher temperature, and the temperature-dependent range of micellar aggregation and half-width of specific heat peak for unimer-micelle transition increase monotonously. Compared with associative polymers, it is found that the magnitude of the transition broadness is determined by the ratio of hydrophobic to hydrophilic blocks, instead of chain length. When \bar{\phi}_{P} is decreased, given a large N_{st}, the temperature-dependent range of micellar aggregation and half-width of specific heat peak initially decease, and then remain nearly constant. It is shown that the transition broadness is concerned with the changes of the relative magnitudes of the eductions of nonstickers and solvents from micellar cores.Comment: 8 pages, 4 figure

    Generating entanglement between microwave photons and qubits in multiple cavities coupled by a superconducting qutrit

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    We discuss how to generate entangled coherent states of four \textrm{microwave} resonators \textrm{(a.k.a. cavities)} coupled by a superconducting qubit. We also show \textrm{that} a GHZ state of four superconducting qubits embedded in four different resonators \textrm{can be created with this scheme}. In principle, \textrm{the proposed method} can be extended to create an entangled coherent state of nn resonators and to prepare a Greenberger-Horne-Zeilinger (GHZ) state of nn qubits distributed over nn cavities in a quantum network. In addition, it is noted that four resonators coupled by a coupler qubit may be used as a basic circuit block to build a two-dimensional quantum network, which is useful for scalable quantum information processing.Comment: 13 pages, 7 figure
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