200,914 research outputs found
Non-renormalization for planar Wess-Zumino model
Using a non-perturbative functional method, where the quantum fluctuations
are gradually set up,it is shown that the interaction of a N=1 Wess-Zumino
model in 2+1 dimensions does not get renormalized. This result is valid in the
framework of the gradient expansion and aims at compensating the lack of
non-renormalization theorems
On the consistency of a non-Hermitian Yukawa interaction
We study different properties of an anti-Hermitian Yukawa interaction,
motivated by a scenario of radiative anomalous generation of masses for the
right-handed sterile neutrinos. The model, involving either a pseudo-scalar or
a scalar, is consistent both at the classical and quantum levels, and
particular attention is given to its properties under improper Lorentz
transformations. The path integral is consistently defined with a Euclidean
signature, and we discuss the energetics of the model, which show that no
dynamical mass generation can occur, unless extra interactions are considered.Comment: 7 pages, comments adde
Self-averaging property of queuing systems
We establish the averaging property for a queuing process with one server,
M(t)/GI/1. It is a new relation between the output flow rate and the input flow
rate, crucial in the study of the Poisson Hypothesis. Its implications include
the statement that the output flow always possesses more regularity than the
input flow.Comment: 18 pages, one typo remove
Non-renormalization for the Liouville wave function
Using an exact functional method, within the framework of the gradient
expansion for the Liouville effective action, we show that the kinetic term for
the Liouville field is not renormalized.Comment: 13 pages Latex, no figure
An alternative approach to dynamical mass generation in QED3
Some quantum properties of QED3 are studied with the help of an exact
evolution equation of the effective action with the bare fermion mass. The
resulting effective theory and the occurrence of a dynamical mass are discussed
in the framework of the gradient expansion
An -Regularization Approach to High-Dimensional Errors-in-variables Models
Several new estimation methods have been recently proposed for the linear
regression model with observation error in the design. Different assumptions on
the data generating process have motivated different estimators and analysis.
In particular, the literature considered (1) observation errors in the design
uniformly bounded by some , and (2) zero mean independent
observation errors. Under the first assumption, the rates of convergence of the
proposed estimators depend explicitly on , while the second
assumption has been applied when an estimator for the second moment of the
observational error is available. This work proposes and studies two new
estimators which, compared to other procedures for regression models with
errors in the design, exploit an additional -norm regularization.
The first estimator is applicable when both (1) and (2) hold but does not
require an estimator for the second moment of the observational error. The
second estimator is applicable under (2) and requires an estimator for the
second moment of the observation error. Importantly, we impose no assumption on
the accuracy of this pilot estimator, in contrast to the previously known
procedures. As the recent proposals, we allow the number of covariates to be
much larger than the sample size. We establish the rates of convergence of the
estimators and compare them with the bounds obtained for related estimators in
the literature. These comparisons show interesting insights on the interplay of
the assumptions and the achievable rates of convergence
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