14,950 research outputs found

    Physics Beyond SM at RHIC with Polarized Protons

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    The capabilities of RHIC with polarized protons to test the Lorentz structure of electroweak interactions and also the properties of MSSM Higgs, should it be discovered, are discussed.Comment: Report to the 14th International Symposium on Spin Physics, October 16-21, 2000, RCNP, Osaka University, Osaka, Japan. To be published in the Proceedings, 6 page

    Strings in five-dimensional anti-de Sitter space with a symmetry

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    The equation of motion of an extended object in spacetime reduces to an ordinary differential equation in the presence of symmetry. By properly defining of the symmetry with notion of cohomogeneity, we discuss the method for classifying all these extended objects. We carry out the classification for the strings in the five-dimensional anti-de Sitter space by the effective use of the local isomorphism between \SO(4,2) and \SU(2,2). We present a general method for solving the trajectory of the Nambu-Goto string and apply to a case obtained by the classification, thereby find a new solution which has properties unique to odd-dimensional anti-de Sitter spaces. The geometry of the solution is analized and found to be a timelike helicoid-like surface

    Spontaneous thermal runaway as an ultimate failure mechanism of materials

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    The first theoretical estimate of the shear strength of a perfect crystal was given by Frenkel [Z. Phys. 37, 572 (1926)]. He assumed that as slip occurred, two rigid atomic rows in the crystal would move over each other along a slip plane. Based on this simple model, Frenkel derived the ultimate shear strength to be about one tenth of the shear modulus. Here we present a theoretical study showing that catastrophic material failure may occur below Frenkel's ultimate limit as a result of thermal runaway. We demonstrate that the condition for thermal runaway to occur is controlled by only two dimensionless variables and, based on the thermal runaway failure mechanism, we calculate the maximum shear strength σc\sigma_c of viscoelastic materials. Moreover, during the thermal runaway process, the magnitude of strain and temperature progressively localize in space producing a narrow region of highly deformed material, i.e. a shear band. We then demonstrate the relevance of this new concept for material failure known to occur at scales ranging from nanometers to kilometers.Comment: 4 pages, 3 figures. Eq. (6) and Fig. 2a corrected; added references; improved quality of figure

    Preparation of macroscopic quantum superposition states of a cavity field via coupling to a superconducting charge qubit

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    We propose how to generate macroscopic quantum superposition states using a microwave cavity containing a superconducting charge qubit. Based on the measurement of charge states, we show that the superpositions of two macroscopically distinguishable coherent states of a single-mode cavity field can be generated by a controllable interaction between a cavity field and a charge qubit. After such superpositions of the cavity field are created, the interaction can be switched off by the classical magnetic field, and there is no information transfer between the cavity field and the charge qubit. We also discuss the generation of the superpositions of two squeezed coherent states.Comment: 6 page

    Japan’s Model of Mobile Ecosystem Success: The Case of NTT DoCoMo

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    This research looks at the adoption of Internet and mobile applications in the United States and Japan. It is the intent ofthis meta-exploratory study to examine factors of success with Japan’s mobile industry over the past decade. Takeshi Natsuno defined the ecosystem as a collection of roles in a collaborative balance. It is here that we began to search for the factors that have had an impact on the success of the mobile industry in Japan over the past two decades. It is the intent of this study to identify and discuss those factors to validate the ecosystem research model and to recommend its use for future research. We found the ecosystem model to be very robust as a model to discuss, categorize, and explain the mobile industry in Japan, leading us to a robust and explanatory push-pull investment model. It is intended that this model will be used for future research. We concluded in this research that risk-taking was the predominant factor influencing the success of the mobile ecosystem in Japan. We found in Japan a clear investment earlier in the process, as the first step in most cases, where mobile carriers, such as NTT DoCoMo, would partner with university labs to develop mobile applications, such as i-Mode and e-payment systems, and then mobile consumers would have new applications and functionality to adopt. The model is very powerful and can be considered for adoption in other countries and maybe for other ecosystems

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    Equilibrium states and their entropy densities in gauge-invariant C*-systems

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    A gauge-invariant C*-system is obtained as the fixed point subalgebra of the infinite tensor product of full matrix algebras under the tensor product unitary action of a compact group. In the paper, thermodynamics is studied on such systems and the chemical potential theory developed by Araki, Haag, Kastler and Takesaki is used. As a generalization of quantum spin system, the equivalence of the KMS condition, the Gibbs condition and the variational principle is shown for translation-invariant states. The entropy density of extremal equilibrium states is also investigated in relation to macroscopic uniformity.Comment: 20 pages, revised in March 200

    Polar Antiferromagnets Produced with Orbital-Order

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    Polar magnetic states are realized in pseudocubic manganite thin films fabricated on high-index substrates, in which a Jahn-Teller (JT) distortion remains an active variable. Several types of orbital-orders were found to develop large optical second harmonic generation, signaling broken-inversion-symmetry distinct from their bulk forms and films on (100) substrates. The observed symmetry-lifting and first-principles calculation both indicate that the modified JT q2 mode drives Mn-site off-centering upon orbital order, leading to the possible cooperation of "Mn-site polarization" and magnetism.Comment: 5 pages, 4 figure

    Finite-time blowup for a complex Ginzburg-Landau equation

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    We prove that negative energy solutions of the complex Ginzburg-Landau equation e−iθut=Δu+∣u∣αue^{-i\theta} u_t = \Delta u+ |u|^{\alpha} u blow up in finite time, where \alpha >0 and \pi /2<\theta <\pi /2. For a fixed initial value u(0)u(0), we obtain estimates of the blow-up time TmaxθT_{max}^\theta as θ→±π/2\theta \to \pm \pi /2 . It turns out that TmaxθT_{max}^\theta stays bounded (respectively, goes to infinity) as θ→±π/2\theta \to \pm \pi /2 in the case where the solution of the limiting nonlinear Schr\"odinger equation blows up in finite time (respectively, is global).Comment: 22 page
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