Quantization of the scalar field in a static quantum metric

We investigate the Hamiltonian formulation of quantum scalar fields in a static quantum metric. We derive a functional integral formula for the propagator. We show that the quantum metric substantially changes the behaviour of the scalar propagator and the effective Yukawa potential.Comment: Latex, 12 page

Phenomenology of Neutrino Mass Matrix

The search for possible mixing patterns of charged leptons and neutrinos is important to get clues of the origin of nearly maximal mixings, since there are some preferred bases of the lepton mass matrices given by underlying theories. We systematically examine the mixing patterns which could lead to large lepton mixing angles. We find out 37 mixing patterns are consistent with experimental data if taking into account phase factors in the mixing matrices. Only 6 patterns of them can explain the observed data without any tuning of parameters, while the others need particular choices for phase values.Comment: revised reference

Twisted Flavors and Tri/bi-Maximal Neutrino Mixing

A new framework for handling flavor symmetry breaking in the neutrino sector is discussed where the source of symmetry breaking is traced to the global property of right-handed neutrinos in extra-dimensional space. Light neutrino phenomenology has rich and robust predictions such as the tri/bi-maximal form of generation mixing, controlled mass spectrum, and no need of flavor mixing couplings in the theory.Comment: 11 page

Effective theories of gauge-Higgs unification models in warped spacetime

We derive four-dimensional (4D) effective theories of the gauge-Higgs unification models in the warped spacetime. The effective action can be expressed in a simple form by neglecting subleading corrections to the wave functions. We have shown in our previous works that some Higgs couplings to the other fields are suppressed by factors that depend on $\bar{\theta}_H$ from the values in the standard model. Here $\bar{\theta}_H$ is the Wilson line phase along the fifth dimension, which characterizes the electroweak symmetry breaking. The effective action derived here explicitly shows a nonlinear structure of the Higgs sector, which clarifies the origins of those suppression factors.Comment: 36 pages, 1 figur

Green functions and dimensional reduction of quantum fields on product manifolds

We discuss Euclidean Green functions on product manifolds P=NxM. We show that if M is compact then the Euclidean field on P can be approximated by its zero mode which is a Euclidean field on N. We estimate the remainder of this approximation. We show that for large distances on N the remainder is small. If P=R^{D-1}xS^{beta}, where S^{beta} is a circle of radius beta, then the result reduces to the well-known approximation of the D dimensional finite temperature quantum field theory to D-1 dimensional one in the high temperature limit. Analytic continuation of Euclidean fields is discussed briefly.Comment: 17 page

(S)fermion Masses in Fat Brane Scenario

We discuss the fermion mass hierarchy and the flavor mixings in the fat brane scenario of a five dimensional SUSY theory. Assuming that the matter fields lives in the bulk, their zero mode wave functions are Gaussians, and Higgs fields are localized on the brane, we find simple various types of the matter configurations generating the mass matrices consistent with experimental data. Sfermion mass spectrum is also discussed using the matter configurations found above. Which type of squark mass spectra (the degeneracy, the decoupling and the alignment) is realized depends on the relative locations of SUSY breaking brane and the brane where Higgs fields are localized.Comment: 18 pages, LaTe

Markov quantum fields on a manifold

We study scalar quantum field theory on a compact manifold. The free theory is defined in terms of functional integrals. For positive mass it is shown to have the Markov property in the sense of Nelson. This property is used to establish a reflection positivity result when the manifold has a reflection symmetry. In dimension d=2 we use the Markov property to establish a sewing operation for manifolds with boundary circles. Also in d=2 the Markov property is proved for interacting fields.Comment: 14 pages, 1 figure, Late

Holographic Techni-dilaton

Techni-dilaton, a pseudo-Nambu-Goldstone boson of scale symmetry, was predicted long ago in the Scale-invariant/Walking/Conformal Technicolor (SWC-TC) as a remnant of the (approximate) scale symmetry associated with the conformal fixed point, based on the conformal gauge dynamics of ladder Schwinger-Dyson (SD) equation with non-running coupling. We study the techni-dilaton as a flavor-singlet bound state of techni-fermions by including the techni-gluon condensate (tGC) effect into the previous (bottom-up) holographic approach to the SWC-TC, a deformation of the holographic QCD with $\gamma_m \simeq 0$ by large anomalous dimension $\gamma_m \simeq 1$. With including a bulk scalar field corresponding to the gluon condensate, we first improve the Operator Product Expansion of the current correlators so as to reproduce gluonic $1/Q^4$ term both in QCD and SWC-TC. We find in QCD about $10\%$ (negative) contribution of gluon condensate to the $\rho$ meson mass. We also calculate the oblique electroweak $S$-parameter in the presence of the effect of the tGC and find that for the fixed value of $S$ the tGC effects dramatically reduce the flavor-singlet scalar (techni-dilaton) mass $M_{\rm TD}$ (in the unit of $F_\pi$), while the vector and axial-vector masses $M_\rho$ and $M_{a_1}$ are rather insensitive to the tGC, where $F_\pi$ is the decay constant of the techni-pion. If we use the range of values of tGC implied by the ladder SD analysis of the non-perturbative scale anomaly in the large $N_f$ QCD near the conformal window, the phenomenological constraint $S \simeq 0.1$ predicts the techni-dilaton mass $M_{\rm TD} \sim 600$ GeV which is within reach of LHC discovery.Comment: 28 pages, 11 eps files, typos corrected, references added, Fig.1 corrected, some discussions added, to be published in PR

Decoherence in QED at finite temperature

We consider a wave packet of a charged particle passing through a cavity filled with photons at temperature T and investigate its localization and interference properties. It is shown that the wave packet becomes localized and the interference disappears with an exponential speed after a sufficiently long path through the cavity.Comment: Latex, 10 page