1,345 research outputs found
Solving the Naturalness Problem by Baby Universes in the Lorentzian Multiverse
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
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 , which
has a sharp peak at . 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 through the action itself, in
our Lorentzian analysis the similar enhancement arises from the front factor of
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
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
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
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
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
- …