1,344 research outputs found

    Solving the Naturalness Problem by Baby Universes in the Lorentzian Multiverse

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    We propose a solution of the naturalness problem in the context of the multiverse wavefunction without the anthropic argument. If we include microscopic wormhole configurations in the path integral, the wave function becomes a superposition of universes with various values of the coupling constants such as the cosmological constant, the parameters in the Higgs potential, and so on. We analyze the quantum state of the multiverse, and evaluate the density matrix of one universe. We show that the coupling constants induced by the wormholes are fixed in such a way that the density matrix is maximized. In particular, the cosmological constant, which is in general time-dependent, is chosen such that it takes an extremely small value in the far future. We also discuss the gauge hierarchy problem and the strong CP problem in this context. Our study predicts that the Higgs mass is 140\pm20 GeV and {\theta}=0.Comment: 35 pages, 11 figures. v2: added Section 5.3 with comments on the Wick rotation of the Lorentzian gravity. v3 some comments adde

    Asymptotically Vanishing Cosmological Constant in the Multiverse

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    We study the problem of the cosmological constant in the context of the multiverse in Lorentzian spacetime, and show that the cosmological constant will vanish in the future. This sort of argument was started from Coleman in 1989, and he argued that the Euclidean wormholes make the multiverse partition a superposition of various values of the cosmological constant Λ\Lambda, which has a sharp peak at Λ=0\Lambda=0. However, the implication of the Euclidean analysis to our Lorentzian spacetime is unclear. With this motivation, we analyze the quantum state of the multiverse in Lorentzian spacetime by the WKB method, and calculate the density matrix of our universe by tracing out the other universes. Our result predicts vanishing cosmological constant. While Coleman obtained the enhancement at Λ=0\Lambda=0 through the action itself, in our Lorentzian analysis the similar enhancement arises from the front factor of eiSe^{iS} in the universe wave function, which is in the next leading order in the WKB approximation.Comment: 17 pages, 7 figures; v2:minor correction

    Stationary measure for two-state space-inhomogeneous quantum walk in one dimension

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    We consider the two-state space-inhomogeneous coined quantum walk (QW) in one dimension. For a general setting, we obtain the stationary measure of the QW by solving the eigenvalue problem. As a corollary, stationary measures of the multi-defect model and space-homogeneous QW are derived. The former is a generalization of the previous works on one-defect model and the latter is a generalization of the result given by Konno and Takei (2015).Comment: 15 pages, revised version, Yokohama Mathematical Journal (in press

    Schwarzschild Space-Time in Gauge Theories of Gravity

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    In Poincar\'e gauge theory of gravity and in \overline{\mbox{Poincar\'e}} gauge theory of gravity, we give the necessary and sufficient condition in order that the Schwarzschild space-time expressed in terms of the Schwarzschild coordinates is obtainable as a torsionless exact solution of gravitational field equations with a spinless point-like source having the energy-momentum density \widetilde{\mbox{\boldmath T}}_\mu^{~\nu}(x) = - Mc^2 \delta_\mu^{~0} \delta_0^{~\nu} \delta^{(3)}(\mbox{\boldmath x}). Further, for the case when this condition is satisfied, the energy-momentum and the angular momentum of the Schwarzschild space-time are examined in their relations to the asymptotic forms of vierbein fields. We show, among other things, that asymptotic forms of vierbeins are restricted by requiring the equality of the active gravitational mass and the inertial mass. Conversely speaking, this equality is violated for a class of vierbeins giving the Schwarzschild metric.Comment: 26 pages, LaTeX, uses amssymb.sty. To appear in Prog. Theor. Phys. 99 (1998

    Phase structure of the large-N reduced gauge theory and generalized Weingarten model

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    We study a generalization of Weingarten model reduced to a point, which becomes the large-N reduced U(N) gauge theory in a special limit. We find that the U(1)^d symmetry is broken one by one, and restored simultaneously as U(1)^d -> U(1)^{d-1} -> ... -> U(1) -> 1 -> U(1)^d as we change the coupling constants. In this model we can develop an efficient algorithm and we can see the phase structure of large-N reduced model clearly, and therefore this model would be useful for the study of the unitary model.Comment: LaTeX-2e, 11 pages with 11 figures; typos correcte

    Comparison of Investigation Modalities for Evaluation of Esophageal Peristaltic Function

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    We reviewed the recent literature concerning investigations of esophageal peristaltic function. The gold standard for the assessment of esophageal peristaltic function is manometry with pH monitoring. Even with this investigation modality, however, we are in fact doing no more than estimating esophageal peristaltic function from the manometry and pH results. With esophageal fluoroscopy and scintigraphy, where we observe esophageal motility, there are problems with radiation exposure and handling of radioactive agents that make widespread use difficult. In recent years, the development of multichannel intraluminal impedance (MII) manometry has allowed simultaneous measurement of intraesophageal pressure and assessment of esophageal peristalsis. Using MII it is also possible to distinguish whether gas or liquid is passing down the esophagus. When manometry is performed in conjunction with transnasal esophagogastroduodenoscopy, with this unique combination it is possible to measure the intraesophageal pressure while actually observing the swallowing motion at the same time. Assessment of esophageal peristaltic function is now moving from simple measurement of intraesophageal pressure to simultaneous impedance manometry and endoscopic observation of esophageal peristalsis itself
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