33,350 research outputs found
Texture and Cofactor Zeros of the Neutrino Mass Matrix
We study Majorana neutrino mass matrices that have two texture zeros, or two
cofactor zeros, or one texture zero and one cofactor zero. The two
texture/cofactor zero conditions give four constraints, which in conjunction
with the five measured oscillation parameters completely determine the nine
independent real parameters of the neutrino mass matrix. We also study the
implications that future measurements of neutrinoless double beta decay and the
Dirac CP phase will have on these cases.Comment: 25 pages, 8 tables, 11 figures. Version to appear in JHE
Parametric generation of quadrature squeezing of mirrors in cavity optomechanics
We propose a method to generate quadrature squeezed states of a moving mirror
in a Fabry-Perot cavity. This is achieved by exploiting the fact that when the
cavity is driven by an external field with a large detuning, the moving mirror
behaves as a parametric oscillator. We show that parametric resonance can be
reached approximately by modulating the driving field amplitude at a frequency
matching the frequency shift of the mirror. The parametric resonance leads to
an efficient generation of squeezing, which is limited by the thermal noise of
the environment.Comment: 4 pages, 2 figure
Neutrino seesaw mechanism with texture zeros
In the context of the Type I seesaw mechanism, we carry out a systematic
study of the constraints that result from zeros in both the Dirac and
right-handed Majorana neutrino mass matrices. We find that most constraints can
be expressed in the standard form with one or two element/cofactor zeros alone,
while there are 9 classes of nonstandard constraints. We show that all the
constraints are stable under one-loop renormalization group running from the
lightest right-handed neutrino mass scale to the electroweak scale. We study
the predictions of the nonstandard constraints for the lightest neutrino mass,
Dirac CP phase and neutrinoless double beta decay.Comment: 43 pages, 9 figures, 3 tables. Version to appear in NP
Correlated two-photon transport in a one-dimensional waveguide side-coupled to a nonlinear cavity
We investigate the transport properties of two photons inside a
one-dimensional waveguide side-coupled to a single-mode nonlinear cavity. The
cavity is filled with a nonlinear Kerr medium. Based on the Laplace transform
method, we present analytic solution of quantum states of the transmitted and
reflected two photons, which are initially prepared in a Lorentzian wave
packet. The solution reveals how quantum correlation between the two photons
emerge after the scattering by the nonlinear cavity. In particular, we show
that the output wave function of the two photons in position space can be
localized in the relative coordinates, which is a feature that may be
interpreted as a two-photon bound state in this waveguide-cavity system.Comment: 9 pages, 5 figure
Partial quark-lepton universality and neutrino CP violation
We study a model with partial quark-lepton universality that can naturally
arise in grand unified theories. We find that constraints on the model can be
reduced to a single condition on the Dirac CP phase in the neutrino
sector. Using our current knowledge of the CKM and PMNS mixing matrices, we
predict at .Comment: 8 pages, 1 figure. Version to appear in the special issue, "Neutrino
Masses and Oscillations 2015", of Advances in High Energy Physic
Spectrum of single-photon emission and scattering in cavity optomechanics
We present an analytic solution describing the quantum state of a single
photon after interacting with a moving mirror in a cavity. This includes
situations when the photon is initially stored in a cavity mode as well as when
the photon is injected into the cavity. In addition, we obtain the spectrum of
the output photon in the resolved-sideband limit, which reveals spectral
features of the single-photon strong-coupling regime in this system. We also
clarify the conditions under which the phonon sidebands are visible and the
photon-state frequency shift can be resolved.Comment: 5 pages, 5 figure
Some Issues in a Gauge Model of Unparticles
We address in a recent gauge model of unparticles the issues that are
important for consistency of a gauge theory, i.e., unitarity and Ward identity
of physical amplitudes. We find that non-integrable singularities arise in
physical quantities like cross section and decay rate from gauge interactions
of unparticles. We also show that Ward identity is violated due to the lack of
a dispersion relation for charged unparticles although the Ward-Takahashi
identity for general Green functions is incorporated in the model. A previous
observation that the unparticle's (with scaling dimension d) contribution to
the gauge boson self-energy is a factor (2-d) of the particle's has been
extended to the Green function of triple gauge bosons. This (2-d) rule may be
generally true for any point Green functions of gauge bosons. This implies that
the model would be trivial even as one that mimics certain dynamical effects on
gauge bosons in which unparticles serve as an interpolating field.Comment: v1:16 pages, 3 figures. v2: some clarifications made and presentation
improved, calculation and conclusion not modified; refs added and updated.
Version to appear in EPJ
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