614 research outputs found
Stabilization of class-B broad-area lasers emission by external optical injection
We theoretically examine the effect of external optical injection on the
spatio-temporal dynamics of class-B broad-area lasers. We demonstrate that
optical injection can efficiently stabilize the intrinsic transverse
instabilities in such lasers associated with both the boundaries of the pumping
area and with the bulk nonlinearities of the active medium. Stabilizing action
of optical injection is shown to be closely related to the suppression of
inherent relaxation oscillations behavior.Comment: 8 pages, 7 figure
Super Tonks-Girardeau state in an attractive one-dimensional dipolar gas
The ground state of a one-dimensional (1D) quantum gas of dipoles oriented
perpendicular to the longitudinal axis, with a strong 1/x^3 repulsive
potential, is studied at low 1D densities . Near contact the dependence of
the many-body wave function on the separation x_{jl} of two particles reduces
to a two-body wave function \Psi_{rel}(x_{jl}). Immediately after a sudden
rotation of the dipoles so that they are parallel to the longitudinal axis,
this wave function will still be that of the repulsive potential, but since the
potential is now that of the attractive potential, it will not be stationary.
It is shown that as nd^2 -> 0 the rate of change of this wave function
approaches zero. It follows that for small values of nd^2, this state is
metastable and is an analog of the super Tonks-Girardeau state of bosons with a
strong zero-range attraction. The dipolar system is equivalent to a spinor
Fermi gas with spin components \sigma_{\uparrow}=\perp (perpendicular to
the longitudinal axis) and \sigma_{\downarrow}=|| (parallel to the longitudinal
axis). A Fermi-Fermi mapping from spinor to spinless Fermi gas followed by the
standard 1960 Fermi-Bose mapping reduces the Fermi system to a Bose gas.
Potential experiments realizing the sudden spin rotation with ultracold dipolar
gases are discussed, and a few salient properties of these states are
accurately evaluated by a Monte Carlo method.Comment: 5 pages, 2 figures, revtex4. Published versio
Anatomy of the “economic miracle”
The authors analyze evolutionary-institutional patterns and factors of economic growth and development on the example of a number of countries which have demonstrated the “economic miracle”. Their research method is a structure of socio-economic genotype which aims at maximizing the economic system outcomes. It is concluded that the “economic miracle” appears when the economic policy and development strategy of a country coincide with the succession (logic) of a cyclic structure of genotype as a driving force of economic evolution.peer-reviewe
Fifty years of the Glauber diffraction theory
In this minireview a historical excursus in theoretical studies related to
the Glauber diffraction theory has been presented with an accent on the recent
developments in this subject.Comment: 22 pages, 4 figures, in russian;v2: an atempt to improve hyphenatio
Non-Ohmic variable-range hopping transport in one-dimensional conductors
We investigate theoretically the effect of a finite electric field on the
resistivity of a disordered one-dimensional system in the variable-range
hopping regime. We find that at low fields the transport is inhibited by rare
fluctuations in the random distribution of localized states that create
high-resistance ``breaks'' in the hopping network. As the field increases, the
breaks become less resistive. In strong fields the breaks are overrun and the
electron distribution function is driven far from equilibrum. The logarithm of
the resistance initially shows a simple exponential drop with the field,
followed by a logarithmic dependence, and finally, by an inverse square-root
law.Comment: Version accepted to Phys. Rev. Let
Search for Low Mass Exotic mesonic structures. Part II: attempts to understand the experimental results
Our previous paper, part I of the same study, shows the different
experimental spectra used to conclude on the genuine existence of narrow,
weakly excited mesonic structures, having masses below and a little above the
pion (M=139.56 MeV) mass. This work \cite{previous} was instigated by the
observation, in the disintegration: pP,
P \cite{park}, of a narrow range of dimuon masses. The
authors conclude on the existence of a neutral intermediate state P, with
a mass M=214.3 MeV 0.5 MeV. We present here some attempts to understand
the possible nature of the structures observed in part I.Comment: 3 pages, 4 figures. Follows 0710.1796. Both replace arXiv:0707.1261
[nucl-ex
Stopping of relativistic ions in multicomponent plasmas
Investigation of the processes of stopping of
charged particles moving in different media is
of significant interest for many realms of Physics,
such that Nuclear Physics, Condensed Matter
Physics, Plasma Physics, etc.
The problem of evaluation of energy losses of
relativistic protons has acquired special importance
recently [1] and, due to the experimental conditions,
it is necessary to estimate relativistic corrections to
the asymptotic form of energy losses in non-ideal
multicomponent plasmas..
Stopping of relativistic ions in multicomponent plasmas
Investigation of the processes of stopping of
charged particles moving in different media is
of significant interest for many realms of Physics,
such that Nuclear Physics, Condensed Matter
Physics, Plasma Physics, etc.
The problem of evaluation of energy losses of
relativistic protons has acquired special importance
recently [1] and, due to the experimental conditions,
it is necessary to estimate relativistic corrections to
the asymptotic form of energy losses in non-ideal
multicomponent plasmas..
Self-consistent analytical solution of a problem of charge-carrier injection at a conductor/insulator interface
We present a closed description of the charge carrier injection process from
a conductor into an insulator. Common injection models are based on single
electron descriptions, being problematic especially once the amount of
charge-carriers injected is large. Accordingly, we developed a model, which
incorporates space charge effects in the description of the injection process.
The challenge of this task is the problem of self-consistency. The amount of
charge-carriers injected per unit time strongly depends on the energy barrier
emerging at the contact, while at the same time the electrostatic potential
generated by the injected charge- carriers modifies the height of this
injection barrier itself. In our model, self-consistency is obtained by
assuming continuity of the electric displacement and the electrochemical
potential all over the conductor/insulator system. The conductor and the
insulator are properly taken into account by means of their respective density
of state distributions. The electric field distributions are obtained in a
closed analytical form and the resulting current-voltage characteristics show
that the theory embraces injection-limited as well as bulk-limited
charge-carrier transport. Analytical approximations of these limits are given,
revealing physical mechanisms responsible for the particular current-voltage
behavior. In addition, the model exhibits the crossover between the two
limiting cases and determines the validity of respective approximations. The
consequences resulting from our exactly solvable model are discussed on the
basis of a simplified indium tin oxide/organic semiconductor system.Comment: 23 pages, 6 figures, accepted to Phys.Rev.
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