1,046 research outputs found
Light Quark Masses in Multi-Quark Interactions
We suggest and discuss in detail a multi-quark three flavor Lagrangian of the
Nambu -- Jona-Lasinio type, which includes a set of effective interactions
proportional to the current quark masses. It is shown that within the dynamical
chiral symmetry breaking regime, the masses of the pseudo Goldstone bosons and
their chiral partners, members of the low lying scalar nonet, are in perfect
agreement with current phenomenological expectations. The role of the new
interactions is analyzed.Comment: 8 pages, published versio
Giant thermoemf in multiterminal superconductor/normal metal mesoscopic structures
We considered a mesoscopic superconductor/normal metal (S/N) structure in
which the N reservoirs are maintained at different temperatures. It is shown
that in the absence of current between the N reservoirs a voltage difference
arises between the superconducting and normal conductors. The voltage
oscillates with increasing phase difference between the
superconductors, and its magnitude does not depend on the small parameter
Comment: Resubmited, some changes to Text and Figure
On the Origin of the Enhancementof CP-violating Charge Asymmetries in Decays Predicted from Chiral Theory
We present an analysis of the enhancement of CP-violating charge asymmetries
in decays. Calculations of decay amplitudes are performed
on the basis of bosonized strong and weak Lagrangians derived from
QCD-motivated quark Lagrangians. We show that the interplay of fourth-order
contributions of chiral Lagrangians for strong interactions and penguin
operators in weak interactions significantly enhances the charge asymmetries.Comment: DESY 92-106, 15
Coherent Charge Transport in Metallic Proximity Structures
We develop a detailed microscopic analysis of electron transport in normal
diffusive conductors in the presence of proximity induced superconducting
correlation. We calculated the linear conductance of the system, the profile of
the electric field and the densities of states. In the case of transparent
metallic boundaries the temperature dependent conductance has a non-monotoneous
``reentrant'' structure. We argue that this behavior is due to nonequilibrium
effects occuring in the normal metal in the presence of both superconducting
correlations and the electric field there. Low transparent tunnel barriers
suppress the nonequilibrium effects and destroy the reentrant behavior of the
conductance. If the wire contains a loop, the conductance shows Aharonov-Bohm
oscillations with the period as a function of the magnetic flux
inside the loop. The amplitude of these oscillations also demonstrates
the reentrant behavior vanishing at and decaying as at relatively
large temperatures. The latter behavior is due to low energy correlated
electrons which penetrate deep into the normal metal and ``feel'' the effect of
the magnetic flux . We point out that the density of states and thus the
``strengh'' of the proximity effect can be tuned by the value of the flux
inside the loop. Our results are fully consistent with recent experimental
findings.Comment: 16 pages RevTeX, 23 Postscript figures, submitted to Phys. Rev.
The development of interactive algorithms for the Mathematical Environment
AbstractThe Mathematical Environment which is under development at the Glushkov Institute of Cybernetics is a system of tools supporting the interactive manipulation of knowledge represented in the form of (formalized) mathematical texts. The system is implemented using a simulator for the Action Language, which has itself been developed using the algebraic programming system APS. The theoretical background of this project is the theory of interaction of agents and environments, constraint solving and the Evidence Algorithm. The main concepts underlying the project and the methodology of its development are explained in this paper in terms of the theory of interaction. The Evidence Algorithm is considered as an example of an interactive algorithm for the Mathematical Environment
Wess-Zumino actions and Dirichlet Boundary Conditions for Super p-branes with Exotic Fractions of Supersymmetry
The general solutions in the models of closed and open superstring and super
p-branes with exotic fractions of the N=1 supersymmetry are considered and the
spontaneously broken character of the symmetry of the models is
established. It is shown that extending these models by Wess-Zumino terms
generates the Dirichlet boundary conditions for superstring and super p-branes.
Using the generalized Wess-Zumino terms new invariant super p-brane
and Dp-brane-like actions preserving fraction of supersymmetry
are proposed. For M=32 these models suggest new superbrane vacua of M-theory
preserving 31 from 32 global supersymmetries.Comment: Latex, 13 page
The Rho-Meson as a Collective Excitation
A model of the rho-meson as a collective excitation of pairs in a
system that obeys the modified Nambu--Jona-Lasinio Lagrangian is proposed. The
rho emerges as a dormant Goldstone boson. The origin of the rho-meson mass is
understood as a result of spontaneous chiral symmetry breaking. The low-energy
dynamics of rho, pi, omega and gamma is consistently described in this new
framework. The model accounts for the origin of the celebrated
Kawarabayashi--Suzuki--Riazuddin--Fayyazuddin relation.Comment: 8 pages, plain LaTe
Charged particles accumulation in drift space of warm electron beam during non-stationary virtual cathod existence
In this paper, the properties and the formation of collective electromagnetic trap for electron beam that propagates in a conducting cylinder are described. It is shown that the electron beam provides the development of an electrostatic instability in the above-mentioned conditions. The instability leads to the appearance of a non-stationary virtual cathode and the formation of electrostatic potential trap. This phenomenon takes place in the central region of the drive space where the amplitude of the electrostatic potential has two maxima. The trap confines electrons during its formation and keeps them inside the drift tube. Once seized in the trap, electrons have rather low temperature and are unstable to diocotron oscillations. During the evolution of diocotron instability the spatial charge redistribution takes place in the cross-section of the beam, which is probably connected with the drift of electrons in longitudinal magnetic field. This process is accompanied not only by azimuthal redistribution of the beam density, but also by radial transfer of electrons across magnetic field, which leads to the increase of the radial beam dimensions and to the injection of electrons onto the walls of the drift chamber. The variations of the radial beam dimensions, and, hence, the spatial charge redistribution in longitudinal direction lead to the corresponding variation of the longitudinal distribution of electric potential, and appearance of self-consistent field of 'potential pit' type in central region of the drive space
Self-consistent penning-malmberg trap
Self-consistent interaction of electrons with electric fields observed in drive space of velocity spread impulse electron beam in longitudinal homogeneous magnetic field during and after the injecting impulse was investigated. The mechanism by which non-neutral electron plasma is accumulated and confined has been studied. Physical behavior of non-neutral plasma has been studied in various non-neutral particle traps, a typical of which is Penning–Malmberg trap. It is a cylindrical trap where the radial motion of the non-neutral particles is constrained by magnetic field, while the longitudinal motions are constrained by electrostatic potential well. When used as an electron trap, the electrons from a thermal cathode are injected parallel to the magnetic field while the cathode side of the electrostatic well is open. By closing the wall dynamically, the electrons that fail to escape during the well closure are trapped. In our experiments the holding electrostatic walls arise self-consistently, simultaneously with injection of an electron beam in the space of drift. Seized there are those particles that at the moment of formation of the trap were in the space of drift
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