273 research outputs found
Absence of Klein's paradox for massive bosons coupled by nonminimal vector interactions
A few properties of the nonminimal vector interactions in the
Duffin-Kemmer-Petiau theory are revised. In particular, it is shown that the
space component of the nonminimal vector interaction plays a peremptory role
for confining bosons whereas its time component contributes to the leakage.
Scattering in a square step potential with proper boundary conditions is used
to show that Klein's paradox does not manifest in the case of a nonminimal
vector coupling
Variational Monte Carlo Calculations of H and He with a relativistic Hamiltonian - II
In relativistic Hamiltonians the two-nucleon interaction is expressed as a
sum of , the interaction in the rest frame,
and the ``boost interaction'' which depends upon the
total momentum and vanishes in the rest frame. The
can be regarded as a sum of four terms: , ,
and ; the first three originate from the
relativistic energy-momentum relation, Lorentz contraction and Thomas
precession, while the last is purely quantum. The contributions of and have been previously calculated with the
variational Monte Carlo method for H and He. In this brief note we
report the results of similar calculations for the contributions of and . These are found to be rather small.Comment: 7 pages, P-94-09-07
Testing of CP, CPT and causality violation with the light propagation in vacuum in presence of the uniform electric and magnetic fields
We have considered the structure of the fundamental symmetry violating part
of the photon refractive index in vacuum in the presence of constant electric
and magnetic fields. This part of the refractive index can, in principle,
contain CPT symmetry breaking terms. Some of the terms violate Lorentz
invariance, whereas the others violate locality and causality. Estimates of
these effects, using laser experiments are considered.Comment: 12 page
Effects due to a scalar coupling on the particle-antiparticle production in the Duffin-Kemmer-Petiau theory
The Duffin-Kemmer-Petiau formalism with vector and scalar potentials is used
to point out a few misconceptions diffused in the literature. It is explicitly
shown that the scalar coupling makes the DKP formalism not equivalent to the
Klein-Gordon formalism or to the Proca formalism, and that the spin-1 sector of
the DKP theory looks formally like the spin-0 sector. With proper boundary
conditions, scattering of massive bosons in an arbitrary mixed vector-scalar
square step potential is explored in a simple way and effects due to the scalar
coupling on the particle-antiparticle production and localization of bosons are
analyzed in some detail
On Equivalence of Duffin-Kemmer-Petiau and Klein-Gordon Equations
A strict proof of equivalence between Duffin-Kemmer-Petiau (DKP) and
Klein-Gordon (KG) theories is presented for physical S-matrix elements in the
case of charged scalar particles interacting in minimal way with an external or
quantized electromagnetic field. First, Hamiltonian canonical approach to DKP
theory is developed in both component and matrix form. The theory is then
quantized through the construction of the generating functional for Green
functions (GF) and the physical matrix elements of S-matrix are proved to be
relativistic invariants. The equivalence between both theories is then proved
using the connection between GF and the elements of S-matrix, including the
case of only many photons states, and for more general conditions - so called
reduction formulas of Lehmann, Symanzik, Zimmermann.Comment: 23 pages, no figures, requires macro tcilate
Recommended from our members
Stockpile surveillance: Past and future
The US nuclear weapon stockpile is entering a different era. Continuous introduction of new weapons into the stockpile, a large production capacity, and underground nuclear testing played important roles in how the nuclear weapons stockpile was managed in the past. These are no longer elements of the nuclear weapons program. Adjustments need to be made to compensate for the loss of these elements. The history of the stockpile indicates that problems have been found in both nuclear and nonnuclear components through a variety of methods including the Stockpile Evaluation Program, stockpile management activities, underground nuclear tests, and research activities. Changes have been made to the stockpile when necessary to assure safety, performance, and reliability. There have been problems found in each of the weapon types expected to be in the stockpile in the year 2000. It is reasonable to expect problems will continue to arise in the stockpile as it ages beyond the original design expectations
Spin 1 fields in Riemann-Cartan space-times "via" Duffin-Kemmer-Petiau theory
We consider massive spin 1 fields, in Riemann-Cartan space-times, described
by Duffin-Kemmer-Petiau theory. We show that this approach induces a coupling
between the spin 1 field and the space-time torsion which breaks the usual
equivalence with the Proca theory, but that such equivalence is preserved in
the context of the Teleparallel Equivalent of General Relativity.Comment: 8 pages, no figures, revtex. Dedicated to Professor Gerhard Wilhelm
Bund on the occasion of his 70th birthday. To appear in Gen. Rel. Grav.
Equations numbering corrected. References update
Bose-Einstein Condensation and Free DKP field
The thermodynamical partition function of the Duffin-Kemmer-Petiau theory is
evaluated using the imaginary-time formalism of quantum field theory at finite
temperature and path integral methods. The DKP partition function displays two
features: (i) full equivalence with the partition function for charged scalar
particles and charged massive spin 1 particles; and (ii) the zero mode sector
which is essential to reproduce the well-known relativistic Bose-Einstein
condensation for both theories.Comment: 12 pages, 2 eps figures. To be published in Physics Letter
Quantum Monte Carlo Studies of Relativistic Effects in Light Nuclei
Relativistic Hamiltonians are defined as the sum of relativistic one-body
kinetic energy, two- and three-body potentials and their boost corrections. In
this work we use the variational Monte Carlo method to study two kinds of
relativistic effects in the binding energy of 3H and 4He. The first is due to
the nonlocalities in the relativistic kinetic energy and relativistic one-pion
exchange potential (OPEP), and the second is from boost interaction. The OPEP
contribution is reduced by about 15% by the relativistic nonlocality, which may
also have significant effects on pion exchange currents. However, almost all of
this reduction is canceled by changes in the kinetic energy and other
interaction terms, and the total effect of the nonlocalities on the binding
energy is very small. The boost interactions, on the other hand, give repulsive
contributions of 0.4 (1.9) MeV in 3H (4He) and account for 37% of the
phenomenological part of the three-nucleon interaction needed in the
nonrelativistic Hamiltonians.Comment: 33 pages, RevTeX, 11 PostScript figures, submitted to Physical Review
- …