5,022 research outputs found
Anomaly of discrete family symmetries and gauge coupling unification
Anomaly of discrete symmetries can be defined as the Jacobian of the
path-integral measure. We assume that an anomalous discrete symmetry at low
energy is remnant of an anomaly free discrete symmetry, and that its anomaly is
cancelled by the Green-Schwarz(GS) mechanism at a more fundamental scale. If
the Kac-Moody levels k_i assume non-trivial values, the GS cancellation
conditions of anomaly modify the ordinary unification of gauge couplings. This
is most welcome, because for a renormalizable model to be realistic any
non-abelian family symmetry, which should not be hardly broken low-energy,
requires multi SU(2)_L doublet Higgs fields. As an example we consider a
recently proposed supersymmetric model with Q_6 family symmetry. In this
example, k_2=1, k_3=3 satisfies the GS conditions and the gauge coupling
unification appears close to the Planck scale.Comment: Talk given at the Summer Institute 2006 (SI2006), APCTP, Pohang,
Korea. 23-30 Aug 200
Neutral Particles and Super Schwinger Terms
Z_2-graded Schwinger terms for neutral particles in 1 and 3 space dimensions
are considered.Comment: 13 page
Magnetic flares in the protoplanetary nebula and the origin of meteorite chondrules
This study proposes and analyzes a model for the chondrule forming heating events based on magnetohydrodynamic flares in the corona of the protoplanetary nebula which precipitate energy in the form of energetic plasma along magnetic field lines down toward the face of the nebula. It is found that flare energy release rates sufficient to melt the prechondrular matter, leading to the formation of the chondrules, can occur in the tenuous corona of a protostellar disk. Energy release rates sufficient to achieve melting require that the ambient magnetic field strength be in the range that has been inferred separately from independent meteorite remanent magnetization studies
Out of equilibrium correlations in the XY chain
We study the transversal XY spin-spin correlations in the non-equilibrium
steady state constructed in \cite{AP03} and prove their spatial exponential
decay close to equilibrium
Estimating terrestrial uranium and thorium by antineutrino flux measurements
Uranium and thorium within the Earth produce a major portion of terrestrial
heat along with a measurable flux of electron antineutrinos. These elements are
key components in geophysical and geochemical models. Their quantity and
distribution drive the dynamics, define the thermal history, and are a
consequence of the differentiation of the Earth. Knowledge of uranium and
thorium concentrations in geological reservoirs relies largely on geochemical
model calculations. This research report describes the methods and criteria to
experimentally determine average concentrations of uranium and thorium in the
continental crust and in the mantle using site-specific measurements of the
terrestrial antineutrino flux. Optimal, model-independent determinations
involve significant exposures of antineutrino detectors remote from nuclear
reactors at both a mid-continental and a mid-oceanic site. This would require
major, new antineutrino detection projects. The results of such projects could
yield a greatly improved understanding of the deep interior of the Earth.Comment: 15 pages, 2 figure
Quantizing the damped harmonic oscillator
We consider the Fermi quantization of the classical damped harmonic
oscillator (dho). In past work on the subject, authors double the phase space
of the dho in order to close the system at each moment in time. For an
infinite-dimensional phase space, this method requires one to construct a
representation of the CAR algebra for each time. We show that unitary dilation
of the contraction semigroup governing the dynamics of the system is a logical
extension of the doubling procedure, and it allows one to avoid the
mathematical difficulties encountered with the previous method.Comment: 4 pages, no figure
Non-anticommutative chiral singlet deformation of N=(1,1) gauge theory
We study the SO(4)x SU(2) invariant Q-deformation of Euclidean N=(1,1) gauge
theories in the harmonic superspace formulation. This deformation preserves
chirality and Grassmann harmonic analyticity but breaks N=(1,1) to N=(1,0)
supersymmetry. The action of the deformed gauge theory is an integral over the
chiral superspace, and only the purely chiral part of the covariant superfield
strength contributes to it. We give the component form of the N=(1,0)
supersymmetric action for the gauge groups U(1) and U(n>1). In the U(1) and
U(2) cases, we find the explicit nonlinear field redefinition (Seiberg-Witten
map) relating the deformed N=(1,1) gauge multiplet to the undeformed one. This
map exists in the general U(n) case as well, and we use this fact to argue that
the deformed U(n) gauge theory can be nonlinearly reduced to a theory with the
gauge group SU(n).Comment: 1+25 pages; v2: corrected eqs.(2.7),(3.12),(4.31-33) and typos; v3:
corrected eqs.(3.29),(4.7),(A.5),(A.21), ref. added, published versio
Another Short and Elementary Proof of Strong Subadditivity of Quantum Entropy
A short and elementary proof of the joint convexity of relative entropy is
presented, using nothing beyond linear algebra. The key ingredients are an
easily verified integral representation and the strategy used to prove the
Cauchy-Schwarz inequality in elementary courses. Several consequences are
proved in a way which allow an elementary proof of strong subadditivity in a
few more lines. Some expository material on Schwarz inequalities for operators
and the Holevo bound for partial measurements is also included.Comment: The proof given here is short and more elementary that in either
quant-ph/0404126 or quant-ph/0408130. The style is intended to be suitable to
classroom presentation. For a Much More Complicated approach, see Section 6
of quant-ph/050619
The Oxidation State of Iron in Silicate Minerals from the Matrices of CO Carbonaceous Chondrites
No abstract available
Leptogenesis with Friedberg-Lee Symmetry
We consider the symmetric Friedberg-Lee (FL) symmetry for the
neutrino sector and show that a specific FL translation leads to the
tribimaximal mixing pattern of the Maki-Nakagawa-Sakata (MNS) matrix. We also
apply the symmetry to the type-I seesaw framework and address the baryon
asymmetry of the universe through the leptogenesis mechanism. We try to
establish a relation between the net baryon asymmetry and CP phases included in
the MNS matrix.Comment: Talk given at International Workshop on Dark Matter, Dark Energy and
Matter-Antimatter Asymmetry, Hsinchu, Taiwan, 20-21 Nov. 2009, to be
published in Modern Physics Letters A, reference adde
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