10,842 research outputs found
Resonant mesomolecule formation
The dtm and ddm resonant fusion rates are calculated taking into account
finite resonance width and subthreshold resonances. Calculations do not use
multipole expansion of the potential. The obtained ddm resonant fusion rates
are compared with recent data at 30-360 K.Comment: 3 pages, 2 figure
One-dimensional strongly interacting electrons with single impurity: conductance reemergence
We show that conductance of 1D channel with one point-like impurity
critically depends on asymptotic behavior of e-e interaction at small momenta k
(about inverse length of a channel). Conductance reemerges (contrary to the
case of point-like repulsive potential) if potential V(k=0)= 0. For example,
this happens if the bare e-e interaction is screened by the charges in the
bulk. The relation of this phenomena to the long-range order present in the
Luttinger model is discussed.Comment: The version of the article will be published in JETP Letter
Kosterlitz-Thouless phase in systems of one-dimensional strongly interacting fermions
We present the ground state wave functions for systems of one-dimensional
interacting fermions. It is shown that these systems undergo phase transitions
similar to the Kosterlitz-Thouless one independently of the interaction
details. In the limit of an infinitely strong interaction the phase transition
turns into the usual second order phase transition in a chiral phase. The
temperature of the phase transition is calculated.Comment: 24 page
Effect of irradiation by He+ and Ga+ ions on 2D-exciton susceptibility of the InGaAs/GaAs quantum-well structures
The effect of irradiation by 30-keV Ga+ and 35-keV He+ ions (in relatively
small doses) on the excitonic reflectivity spectra of single InGaAs/GaAs
quantum-well structures is studied. It is found that the irradiation results in
decreasing intensity and broadening of the excitonic resonances in the
reflectivity spectra for all the doses. It is shown that these changes are not
related to a decrease of the exciton transition oscillator strength and,
therefore, to the irradiation-induced destruction of the excitonic states, but
can be rather ascribed to a common cause, namely, to inhomogeneous broadening
of the excitonic resonances proportional to the exposure dose.A tentative model
of the irradiation-induced broadening is considered, with the mechanism of the
process being a consequence of scat-tering of the 2D excitons by structural
defects associated with Ga(In) and As vacancies arising upon collisions of the
high-energy ions with regular atoms of the crystal structure. The model is used
to compare experimental dependence of efficiency of the Ga+-ion-induced
broad-ening on distance of the quantum well from the irradiated surface with a
similar dependence calculated using the Monte-Carlo technique. A discrepancy
between the results of simulation and experimental data is discussed
Pion wave function from the instanton vacuum model
The pion wave function is computed in the low energy effective theory
inspired by the instanton vacuum model. The resultat is numerically rather
close to the asymptotical wave function.Comment: 7 pages, 1 figur
Light cone nucleon wave function in the quark-soliton model
The light-cone wave function of the nucleon is calculated in the limit
N_c -> infinity in the quark-soliton model inspired by the theory of the
instanton vacuum of QCD. The technique of the finite time evolution operator is
used in order to derive expressions for all components of the Fock vector
describing the nucleon in the infinite momentum frame. It is shown that nucleon
wave function for large N_c can be expressed in terms of the wave function of
the discrete level in the self-consistent meson field and light cone wave
functions of 1,2, etc mesons. The 3-quark components of the nucleon and
Delta-resonance are estimated. Wave function of the nucleon appears to be
positive in the whole region of x and it has rather small asymmetry. It differs
strongly both from Chernyak-Zhitnitsky wave function and the asymptotic one.
Large momentum transfer asymptotic of the electromagnetic and axial form
factors is discussed.Comment: 23 pages, 2 figures, references adde
Plasmons in QED Vacuum
The problem of longitudinal oscillations of an electric field and a charge
polarization density in QED vacuum is considered. Within the framework of
semiclassical analysis, we calculate time-periodic solutions of bosonized
(1+1)-dimensional QED (massive Schwinger model). Applying the Bohr--Sommerfeld
quantization condition, we determine the mass spectrum of charge-zero bound
states (plasmons) which correspond in quantum theory to the found classical
solutions. We show that the existence of such plasmons does not contradict any
fundamental physical laws and study qualitatively their excitation in
(3+1)-dimensional real world.Comment: 9 pages, 7 figure
Spontaneous symmetry breaking in a system of strongly interacting multicomponent fermions (electrons with spin and conducting nanotubes)
We have calculated the ground state wave functions for a systems of
multicomponent interacting fermions. We show that it describes the state with
spontaneously broken chiral symmetry. In the limit of an infinitely strong
interaction it turns into a phase with a finite density of chiral complexes.
The number of particles constituting a complex depends on the number of fermion
components. For example, in the case of two component electrons (spin) the
condensate is built of four-particle complexes consisting of two "right"
electrons and two "left" holes with the opposite spins.Comment: 13 page
Exact Axisymmetric Solutions of the Maxwell Equations in a Nonlinear Nondispersive Medium
The features of propagation of intense waves are of great interest for theory
and experiment in electrodynamics and acoustics. The behavior of nonlinear
waves in a bounded volume is of especial importance and, at the same time, is
an extremely complicated problem. It seems almost impossible to find a rigorous
solution to such a problem even for any model of nonlinearity. We obtain the
first exact solution of this type. We present a new method for deriving exact
solutions of the Maxwell equations in a nonlinear medium without dispersion and
give examples of the obtained solutions that describe propagation of
cylindrical electromagnetic waves in a nonlinear nondispersive medium and free
electromagnetic oscillations in a cylindrical cavity resonator filled with such
a medium.Comment: 5 pages, 3 figure
Polariton transport in one-dimensional channels
We study theoretically the transport of linearly polarized exciton-polaritons
in a quasi one-dimensional microcavity channel separating two polariton
condensates generated by optical pumping. The direction and value of mass and
spin currents are controlled by the relative phase and polarisation of two
condensates, as in the stationary Josephson effect. However, due to dissipation
and particle-particle interactions, the current denisty is inhomogeneous: it
strongly depends on the coordinate along the axis of the channel. A stationary
spin domain can be created in the channel, its position would be sensitive to
the phase difference between two bordering condensates.Comment: 6 pages, 5 figures. Second version of the paper is expanded to
clarify the explanation. Several new references are adde
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