3,158 research outputs found
On Whitney type inequalities for local anisotropic polynomial approximation
We prove a multivariate Whitney type theorem for the local anisotropic
polynomial approximation in with . Here is a
-parallelepiped in \RR^d with sides parallel to the coordinate axes. We
consider the error of best approximation of a function by algebraic
polynomials of fixed degree at most in variable ,
and relate it to a so-called total mixed modulus of smoothness appropriate to
characterizing the convergence rate of the approximation error. This theorem is
derived from a Johnen type theorem on equivalence between a certain
K-functional and the total mixed modulus of smoothness which is proved in the
present paper.Comment: 12 pages; the proofs of Theorems 1.2 and 2.2 and Lemma 3.1 are
revised; typos are corrected; Acknowledgments are added; the results are
unchange
Revisiting Minimal Lepton Flavour Violation in the Light of Leptonic CP Violation
The Minimal Lepton Flavour Violation (MLFV) framework is discussed after the
recent indication for CP violation in the leptonic sector. Among the three
distinct versions of MLFV, the one with degenerate right-handed neutrinos will
be disfavoured, if this indication is confirmed. The predictions for leptonic
radiative rare decays and muon conversion in nuclei are analysed, identifying
strategies to disentangle the different MLFV scenarios. The claim that the
present anomalies in the semi-leptonic -meson decays can be explained within
the MLFV context is critically re-examined concluding that such an explanation
is not compatible with the present bounds from purely leptonic processes.Comment: 36 pages, 4 figures. V2: References added; version accepted for
publication on JHE
On "the authentic damping mechanism" of the phonon damping model
Some general features of the phonon damping model are presented. It is
concluded that the fits performed within this model have no physical content
Radiative Emission of Neutrino Pairs in Atoms and Light Sterile Neutrinos
The process of Radiative Emission of Neutrino Pair (RENP) in atoms is
sensitive to the absolute neutrino mass scale, the type of spectrum neutrino
masses obey and the nature - Dirac or Majorana - of massive neutrinos. We
analyse the possibility to test the hypothesis of existence of neutrinos with
masses at the eV scale coupled to the electron in the weak charged lepton
current in an RENP experiment. The presence of eV scale neutrinos in the
neutrino mixing is associated with the existence of sterile neutrinos which mix
with the active flavour neutrinos. At present there are a number of hints for
active-sterile neutrino oscillations driven by .
We perform a detailed analysis of the RENP phenomenology within the "3 + 1"
scheme with one sterile neutrino.Comment: LATEX file, 19 pages, the effects of the 3-4 mixing taken into
account, one table and four figures added, version to be published in Phys.
Lett.
A theorem of Tits type for compact Kahler manifolds
We prove a theorem of Tits type about automorphism groups for compact Kahler
manifolds, which has been conjectured in the paper [KOZ].Comment: Inventiones Mathematicae (to appear), 11 page
COVID-19 - Revealing Unaddressed Systemic Barriers in the 45th Anniversary of the Southeast Asian American Experience
2020 marks the 45th year anniversary of the Southeast Asian American (SEAA) experience, starting with the first wave of refugees who fled Cambodia, Laos, and Viet Nam as a result of American occupation and wars throughout the region. Collectively, this community is the largest community of refugees ever to be resettled in America. Yet despite four decades in this country, Southeast Asian Americans continue to face disparate challenges like other low-income, immigrant, refugee, communities of color — ranging from poverty, to educational inequity, health disparities, and harsh immigration policies. COVID-19 pandemic has also revealed and exacerbated systemic barriers that have always existed for Southeast Asian American communities. This paper explores those impacts in economic, education, health, and immigration enforcement and concludes with thoughts on the way forward
Tunneling into Nonequilibrium Luttinger Liquid with Impurity
We evaluate tunneling rates into/from a voltage biased quantum wire
containing weak backscattering defect. Interacting electrons in such a wire
form a true nonequilibrium state of the Luttinger liquid (LL). This state is
created due to inelastic electron backscattering leading to the emission of
nonequilibrium plasmons with typical frequency . The
tunneling rates are split into two edges. The tunneling exponent at the Fermi
edge is positive and equals that of the equilibrium LL, while the exponent at
the side edge is negative if Coulomb interaction is not too strong.Comment: 4+ pages, 5 figure
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