2,486 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
Covariance and PCA for Categorical Variables
Covariances from categorical variables are defined using a regular simplex
expression for categories. The method follows the variance definition by Gini,
and it gives the covariance as a solution of simultaneous equations. The
calculated results give reasonable values for test data. A method of principal
component analysis (RS-PCA) is also proposed using regular simplex expressions,
which allows easy interpretation of the principal components. The proposed
methods apply to variable selection problem of categorical data USCensus1990
data. The proposed methods give appropriate criterion for the variable
selection problem of categoricalComment: 12 pages, 5 figure
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
Fermionic Dark Matter in Radiative Inverse Seesaw Model with U(1)_{B-L}
We construct a radiative inverse seesaw model with local B-L symmetry, and
investigate the flavor structure of the lepton sector and the fermionic Dark
Matter. Neutrino masses are radiatively generated through a kind of inverse
seesaw framework. The PMNS matrix is derived from each mixing matrix of the
neutrino and charged lepton sector with large Dirac CP phase. We show that the
annihilation processes via the interactions with Higgses which are independent
on the lepton flavor violation, have to be dominant in order to satisfy the
observed relic abundance by WMAP. The new interactions with Higgses allow us to
be consistent with the direct detection result reported by XENON100, and it is
possible to verify the model by the exposure of XENON100 (2012).Comment: 15 pages, 1 table, 5 figures; version accepted for publication in
Physical Review
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