8,220 research outputs found
Comment on "Exact results for survival probability in the multistate Landau-Zener model"
We correct the proof of Brundobler-Elser formula (BEF) provided in [2004
\textit{J. Phys. B: At. Mol. Opt. Phys.} \textbf{37} 4069] and continued in
Appendix of [2005 \textit{J. Phys. B: At. Mol. Opt. Phys.} \textbf{38} 907].
After showing that some changes of variables employed in these articles are
used erroneously, we propose an alternative change of variables which solves
the problem. In our proof, we reveal the connection between the BEF for a
general -level Landau-Zener system and the exactly solvable bow-tie model.
The special importance of the diabatic levels with maximum/minimum slope is
emphasized throughout.Comment: 10 page
NJL interaction derived from QCD: vector and axial-vector mesons
In previous works effective non-local NJL model was
derived in the framework of the fundamental QCD. All the parameters of the
model are expressed through QCD parameters: current light quark mass and
average non-perturbative . The results for scalar and pseudo-scalar
mesons are in satisfactory agreement to existing data. In the present work the
same model without introduction of any additional parameters is applied for a
description of masses and strong decay widths of - and -mesons. The
results for both scalar and vector sectors agree with data with only one
adjusted parameter , with account of average ,
which is obtained in a previous work as well.Comment: 19 pages, 2 figures, 1 tabl
Even and odd symplectic and K\"ahlerian structures on projective superspaces
Supergeneralization of \DC P(N) provided by even and odd K\"ahlerian
structures from Hamiltonian reduction are construct.Operator which
used in Batalin-- Vilkovisky quantization formalism and mechanics which are
bi-Hamiltonian under corresponding even and odd Poisson brackets are
considered.Comment: 19 page
Dynamics of Fluxon Lattice in Two Coupled Josephson Junctions
We study theoretically the dynamics of a fluxon Lattice (FL) in two coupled
Josephson junctions. We show that when the velocity of the moving FL exceeds
certain values , sharp resonances arise in the system which are
related to the excitation of the optical and acoustic collective modes. In the
interval a reconstruction of the FL occurs. We also establish that
one can excite localized nonlinear distortions (dislocations) which may
propagate through the FL and carry an arbitrary magnetic flux.Comment: 4 pages, 3 figures, corected typo
Pion Polarizability in the NJL model and Possibilities of its Experimental Studies in Coulomb Nuclear Scattering
The charge pion polarizability is calculated in the Nambu-Jona-Lasinio model,
where the quark loops (in the mean field approximation) and the meson loops (in
the approximation) are taken into account. We show that quark loop
contribution dominates, because the meson loops strongly conceal each other.
The sigma-pole contribution plays the main role and
contains strong t-dependence of the effective pion polarizability at the region
. Possibilities of experimental test of this sigma-pole
effect in the reaction of Coulomb Nuclear Scattering are estimated for the
COMPASS experiment.Comment: 11 pages, 8 figure
The Finite Basis Problem for Kiselman Monoids
In an earlier paper, the second-named author has described the identities
holding in the so-called Catalan monoids. Here we extend this description to a
certain family of Hecke--Kiselman monoids including the Kiselman monoids
. As a consequence, we conclude that the identities of
are nonfinitely based for every and exhibit a finite
identity basis for the identities of each of the monoids and
.
In the third version a question left open in the initial submission has beed
answered.Comment: 16 pages, 1 table, 1 figur
Gravitational-Recoil Effects on Fermion Propagation in Space-Time Foam
Motivated by the possible experimental opportunities to test quantum gravity
via its effects on high-energy neutrinos propagating through space-time foam,
we discuss how to incorporate spin structures in our D-brane description of
gravitational recoil effects in vacuo. We also point to an interesting
analogous condensed-matter system. We use a suitable supersymmetrization of the
Born-Infeld action for excited D-brane gravitational backgrounds to argue that
energetic fermions may travel slower than the low-energy velocity of light:
\delta c / c \sim -E/M. It has been suggested that Gamma-Ray Bursters may emit
pulses of neutrinos at energies approaching 10^{19} eV: these would be
observable only if M \gsim 10^{27} GeV.Comment: 18 pages LaTe
- …