10,389 research outputs found

    Spacetime and universal soft modes: Black holes and beyond

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    Recently, a coherent picture of the quantum mechanics of an evaporating black hole has been presented which reconciles unitarity with the predictions of the equivalence principle. The thermal nature of a black hole as viewed in a distant reference frame arises from entanglement between the hard and soft modes generated by the chaotic dynamics at the string scale. In this paper, we elaborate on this picture, particularly emphasizing the importance of the chaotic nature of the string (UV) dynamics across all low-energy species in generating large (IR) spacetime behind the horizon. Implications of this UV/IR relation include O(1) breaking of global symmetries at the string scale and a self-repair mechanism of black holes restoring the smoothness of their horizons. We also generalize the framework to other systems, including Rindler, de Sitter, and asymptotically flat spacetimes, and find a consistent picture in each case. Finally, we discuss the origin of the particular construction adopted in describing the black hole interior as well as the outside of a de Sitter horizon. We argue that the construction is selected by the quantum-to-classical transition, in particular, the applicability of the Born rule in a quantum mechanical world

    Two-neutron transfer reactions and shape phase transitions in the microscopically-formulated interacting boson model

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    Two-neutron transfer reactions are studied within the interacting boson model based on the nuclear energy density functional theory. Constrained self-consistent mean-field calculations with the Skyrme energy density functional are performed to provide microscopic input to completely determine the Hamiltonian of the IBM. Spectroscopic properties are calculated only from the nucleonic degrees of freedom. This method is applied to study the (t,p)(t,p) and (p,t)(p,t) transfer reactions in the assorted set of rare-earth nuclei 146158^{146-158}Sm, 148160^{148-160}Gd, and 150162^{150-162}Dy, where spherical-to-axially-deformed shape phase transition is suggested to occur at the neutron number N90N\approx 90. The results are compared with those from the purely phenomenological IBM calculations, as well as with the available experimental data. The calculated (t,p)(t,p) and (p,t)(p,t) transfer reaction intensities, from both the microscopic and phenomenological IBM frameworks, signal the rapid nuclear structural change at particular nucleon numbers.Comment: 12 pages, 12 figures, 2 table

    The Static Quantum Multiverse

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    We consider the multiverse in the intrinsically quantum mechanical framework recently proposed in Refs. [1,2]. By requiring that the principles of quantum mechanics are universally valid and that physical predictions do not depend on the reference frame one chooses to describe the multiverse, we find that the multiverse state must be static---in particular, the multiverse does not have a beginning or end. We argue that, despite its naive appearance, this does not contradict observation, including the fact that we observe that time flows in a definite direction. Selecting the multiverse state is ultimately boiled down to finding normalizable solutions to certain zero-eigenvalue equations, analogous to the case of the hydrogen atom. Unambiguous physical predictions would then follow, according to the rules of quantum mechanics.Comment: 27 pages, 2 figures; a typo in the abstract correcte

    Variations on Supersymmetry Breaking and Neutrino Spectra

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    The problem of generating light neutrinos within supersymmetric models is discussed. It is shown that the hierarchy of scales induced by supersymmetry breaking can give rise to suppression factors of the correct order of magnitude to produce experimentally allowed neutrino spectra.Comment: 18 pages, LaTeX, Contribution to "Neutrino Workshop", Fuji-Yoshida, Japan, August 200

    A Mechanism of Spin-Triplet Superconductivity in Hubbard Model on Triangular La ttice: Application to UNi_2Al_3

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    We discuss the possibility of spin-triplet superconductivity in a two-dimensional Hubbard model on a triangular lattice within the third-order perturbation theory. When we vary the symmetry in the dispersion of the bare energy band from D_2 to D_6, spin-singlet superconductivity in the D_2-symmetric system is suppressed and we obtain spin-triplet superconductivity in near the D_6-symmetric system. In this case, it is found that the vertex terms, which are not included in the interaction mediated by the spin fluctuation, are essential for realizing the spin-triplet pairing. We point out the possibility that obtained results correspond to the difference between the superconductivity of UNi_2Al_3 and that of UPd_2Al_3.Comment: 11pages, 5figure

    Rat white adipocytes activate p85/p110 PI3K and induce PM GLUT4 in response to adrenoceptor agonists or aluminum fluoride

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    Adipocyte responses to adrenergic and ß-adrenoceptor(-AR) (adrenoceptor) regulation are not sufficiently understood, and information helpful for elucidating the adrenoceptor-responsive machinery is insufficient. Here we show by using immunoprecipitated kinase analysis with a phosphatidylinositol 3-kinase (PI3K) p85 antibody that PI3K activation was induced by treatment with 10 or 100 µM norepinephrine (NE) for 15 min or with 10 mM aluminum fluoride (AF, a guanosine triphosphate (GTP)-binding (G) protein activator) for 20 min in white adipocytes (rat epididymal adipocytes) and that treatment with pertussis toxin (PTX, a G-protein inactivator) inhibited PI3K activation induced by the 20-min treatment with AF in the cells. In addition, western blot analysis revealed that glucose transporter 4 (GLUT4) level in the adipocyte plasma membrane (PM) fraction was increased by treatment with 10 µM NE, 100 µM dobutamine (DOB, a ß1-AR agonist), or 0.1 µM CL316243 (CL, a ß3-AR agonist) for 30 min or with 10 mM AF for 20 min. NE or AF treatment triggered 2-deoxyglucose (2-DG) uptake into adipocytes under the above conditions. Our results advance the understanding of responses to adrenoceptor regulation in white adipocytes and provide possible clues for clarifying the machinery involved in adrenergic and ß-AR responses in the cells

    Stable skyrmions from extra dimensions

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    We show that skyrmions arising from compact five dimensional models have stable sizes. We numerically obtain the skyrmion configurations and calculate their size and energy. Although their size strongly depends on the magnitude of localized kinetic-terms, their energy is quite model-independent ranging between 50-65 times F_pi^2/m_rho, where F_pi is the Goldstone decay constant and m_rho the lowest Kaluza-Klein mass. These skyrmion configurations interpolate between small 4D YM instantons and 4D skyrmions made of Goldstones and a massive vector boson. Contrary to the original 4D skyrmion and previous 5D extensions, these configurations have sizes larger than the inverse of the cut-off scale and therefore they are trustable within our effective 5D approach. Such solitonic particles can have interesting phenomenological consequences as they carry a conserved topological charge analogous to baryon number.Comment: 20 pages, 3 figure
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