42,295 research outputs found
Comment on "Wave functions for a Duffin-Kemmer-Petiau particle in a time-dependent potential"
It is shown that the paper "Wave functions for a Duffin-Kemmer-Petiau
particle in a time-dependent potential", by Merad and Bensaid [J. Math. Phys.
48, 073515 (2007)] is not correct in using inadvertently a non-Hermitian
Hamiltonian in a formalism that does require Hermitian Hamiltonians.Comment: 2 page
Corroborating the equivalence between the Duffin-Kemmer-Petiau and the Klein-Gordon and Proca equations
It is shown that the Hamiltonian version of the Duffin-Kemmer-Petiau theory
with electromagnetic coupling brings about a source term at the current. It is
also shown that such a source term disappears from the scenario if one uses the
correct physical form for the Duffin-Kemmer-Petiau field, regardless the choice
for representing the Duffin-Kemmer-Petiau matrices. This result is used to fix
the ambiguity in the electromagnetic coupling in the Duffin-Kemmer-Petiau
theory. Moreover, some widespread misconceptions about the Hermiticity in the
Duffin-Kemmer-Petiau theory are discussed.Comment: 13 pages, to appears in Phys. Rev.
On the bound-state spectrum of a nonrelativistic particle in the background of a short-ranged linear potential
The nonrelativistic problem of a particle immersed in a triangular potential
well, set forth by N.A. Rao and B.A. Kagali, is revised. It is shown that these
researchers misunderstood the full meaning of the potential and obtained a
wrong quantization condition. By exploring the space inversion symmetry, this
work presents the correct solution to this problem with potential applications
in electronics in a simple and transparent way
Missing solution in a Cornell potential
Missing bound-state solutions for fermions in the background of a Cornell
potential consisting of a mixed scalar-vector-pseudoscalar coupling is
examined. Charge-conjugation operation, degeneracy and localization are
discussed
Relativistic Effects of Mixed Vector-Scalar-Pseudoscalar Potentials for Fermions in 1+1 Dimensions
The problem of fermions in the presence of a pseudoscalar plus a mixing of
vector and scalar potentials which have equal or opposite signs is
investigated. We explore all the possible signs of the potentials and discuss
their bound-state solutions for fermions and antifermions. The cases of mixed
vector and scalar P\"{o}schl-Teller-like and pseudoscalar kink-like potentials,
already analyzed in previous works, are obtained as particular cases
Unified Treatment of Mixed Vector-Scalar Screened Coulomb Potentials for Fermions
The problem of a fermion subject to a general mixing of vector and scalar
screened Coulomb potentials in a two-dimensional world is analyzed and
quantization conditions are found.Comment: 7 page
Radiative corrections of to decays
The electromagnetic radiative corrections to the ( is a vector meson and a charged
lepton) decay rates are evaluated using the cutoff method to regularize virtual
corrections and incorporating intermediate resonance states in the real-photon
amplitude to extend the region of validity of the soft-photon approximation.
The electromagnetic and weak form factors of hadrons are assumed to vary
smoothly over the energies of virtual and real photons under consideration. The
cutoff dependence of radiative corrections upon the scale that
separates the long- and short-distance regimes is found to be mild and is
considered as an uncertainty of the calculation. Owing to partial cancellations
of electromagnetic corrections evaluated over the three- and four-body regions
of phase space, the photon-inclusive corrected rates are found to be dominated
by the short-distance contribution. These corrections will be relevant for a
precise determination of the quark mixing angles by testing isospin
symmetry when measurements of semileptonic rates of charged and neutral
mesons at the few percent level become available. For completeness, we also
provide numerical values of radiative corrections in the three-body region of
the Dalitz plot distributions of these decays.Comment: Further comments and two references adde
On Duffin-Kemmer-Petiau particles with a mixed minimal-nonminimal vector coupling and the nondegenerate bound states for the one-dimensional inversely linear background
The problem of spin-0 and spin-1 bosons in the background of a general mixing
of minimal and nonminimal vector inversely linear potentials is explored in a
unified way in the context of the Duffin-Kemmer-Petiau theory. It is shown that
spin-0 and spin-1 bosons behave effectively in the same way. An orthogonality
criterion is set up and it is used to determine uniquely the set of solutions
as well as to show that even-parity solutions do not exist.Comment: 10 page
Gap and pseudogap evolution within the charge-ordering scenario for superconducting cuprates
We describe the spectral properties of underdoped cuprates as resulting from
a momentum-dependent pseudogap in the normal state spectrum. Such a model
accounts, within a BCS approach, for the doping dependence of the critical
temperature and for the two-parameter leading-edge shift observed in the
cuprates. By introducing a phenomenological temperature dependence of the
pseudogap, which finds a natural interpretation within the stripe
quantum-critical-point scenario for high-T_c superconductors, we reproduce also
the T_c-T^* bifurcation near optimum doping. Finally, we briefly discuss the
different role of the gap and the pseudogap in determining the spectral and
thermodynamical properties of the model at low temperatures.Comment: 13 pages (EPY style), 7 enclosed figures, to appear on Eur. Phys. J.
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