We study the relationship between the error in the discrimination of two possible evolution paths of a quantum system and its initial state. We consider the case of two-level discrimination when there are no fluctuations of nonquantum nature (the system is in a pure state). It is shown that two evolution paths can be distinguished only when the indeterminacy in the difference of quantum phases ($\sigma _{\phi}$) in the possible evolution paths is greater than unity; the discrimination error is then independent of the average value of the phase difference.
Show AbstractWe consider the temperature correction to the ground-state energy of an electron in a magnetic field. The allowance for temperature effects leads to an increase of the anomalous Schwinger magnetic moment of the electron.
Show AbstractWe consider the nonstationary diffraction of the front of a plane wave from a half plane in a rotating compressible liquid. We construct and study the exact solution, and calculate the limiting amplitude for the problem under consideration at long times.
Show AbstractWe develop an alternative variant of the transition to the four-dimensional space-time in the Kaluza-Klein theories: instead of averaging over the additional coordinates, we carry out contraction to a four-dimensional submanifold. It is shown that in this approach, in addition to the usual Kaluza-Klein Lagrangian, the total Lagrangian of the theory contains terms which are analogous to the Kiggs terms. This leads to spontaneous breaking of the gage symmetry.
Show AbstractWe analyze numerically the overlap integral of wavefunctions of the initial and final electron states in capture reactions $He^{2+} + H\to He^{+} + H^{+}$ and $Li^{3+} + H\to Li^{2+}+ H^+$ in the energy range of the incident ion 20-100 keV/nucleon. The calculations show that the overlap integral must be taken into account only in the analysis of electron capture from the 1s shell of the target to the 1s shell of the incident ion.
Show AbstractWe analyze the results of a study of the separations between hadron interactions in lead at energies 20-100 TeV obtained by the method of X-ray emulsion chambers exposed in the mountains. It is shown that it is necessary to adopt the value of the total inelasticity coefficient equal to $\langle K \rangle \simeq 0,8$.
Show AbstractOne of the main factors which determine the sensitivity of a Weber-type detector of gravitational radiation is the mechanical quality of the antenna. In this work, we calculate the effect of coupling between the longitudinal and bending modes of oscillation on the Q factor of the fundamental longitudinal mode for an antenna of a complex form which differs from a circular cylinder. The calculations are confirmed experimentally by the study of damping on models of antenna from silicon monocrystals.
Show AbstractWe study experimentally the energy distribution function of electrons in a magnetoactive plasma. We find that this distribution function is close to the Maxwell distribution in a wide range of the magnetic field, including the region $B>B_{cr}$. An appreciable deviation of the distribution function from the Maxwell distribution is observed when ionization waves exist in the discharge. It is shown experimentally that the electron diffusion to the probe in magnetic fields up to 0.25 T can be described by a classical law.
Show AbstractWe consider a four-dimensional dynamical system with a competitive interaction, which is useful for the description of various ecological and physical processes. We find the regions which correspond to the existence of a strange attractor in the system, and study the possibility of controlling the autostochastic system by a parametric interaction.
Show AbstractThe method of continuum integration is used to consider the effects of multiple scattering (including backscattering) in a randomly inhomogeneous medium. We calculate the average field, average reflection coefficient and the effective dielectric permittivity of a layer which contains three-dimensional small-scale fluctuations of the dielectric permittivity.
Show AbstractWe calculate the characteristics of the signal in nonstationary active spectroscopy with allowance for the finite duration and incoherence of laser pulses used in the excitation and probing of molecular vibrations of a substance. It is shown that in the short-pulse regime the form and duration of the observed pulsed response is determined only by the properties of the medium under investigation and is independent of the coherence of the laser pulses. The energy of the pulsed response decreases with increasing coherence.
Show AbstractWe analyze the nonlinear distortion of a two-dimensional light beam with a profiled amplitude distribution after passage through a layer of moving defocusing medium. It is shown that this beam suffers a nonlinear self-interaction which is smaller than that of a Gaussian beam. We obtain the condition for optimal defocusing.
Show AbstractWe obtain an evolution equation for waves in media with a quadratic nonlinearity and an arbitrary linear damping. This equation is used to analyze numerically the suppression of nonlinear damping of a harmonic sound wave in a medium which contains a resonant absorber at the frequency of the second harmonic. We find the region of values of the absorption coefficient and the region of the Q factors of the absorber in which this effect can be observed.
Show AbstractWe make quantitative comparison of the theory of thermooptical generation for a planar problem with the experimental data on the thermooptical excitation of sound. The sound is excited by a pulsed $CO_2$ laser. The theoretical and experimental data are in good agreement.
Show AbstractIt is shown that the optical activity of molecules which form the cholesteric liquid crystals must lead to a vectorial orientational order. It is suggested that the structure of this new type can be identified from the observation of "weak" optical activity.
Show AbstractWe present the results of laboratory experiments which indicate that a hydrocarbon film has a considerable effect on the gas exchange between the water-air boundary under a weak collapse of waves and thermal convection. We analyze the data on the pollution of the North Atlantic by films of oil products. We estimate the rates of gas exchange between the ocean and atmosphere (on the example of the North Atlantic) caused by oil pollution.
Show AbstractWe study a model of galaxies of the EE type with the average integral characteristics which were obtained earlier, and the density distribution which corresponds to the King's law. For this model, we study the region of possible motion of a material point in the framework of the problem of two stationary centers. The results obtained in this work are in favor of active gas exchange during the star-formation and supernovae explosions in the components of the pair which have an effect on the evolution of these double systems at the early stages of their existence.
Show AbstractThe effect of thermal processing of the structure of the amorphous alloy $Co_{75}Fe_5B_{20}$ is studied by measuring the NMR spectra, temperature dependences of the magnetization, and by X-ray structure analysis. The obtained data show that already in the initial amorphous state of the alloy $Co_{75}Fe_5B_{20}$ there exist regions with local environment similar to the crystal structure of $Co_3B$. It is assumed that the replacement of cobalt atoms by iron atoms assists the formation of these regions.
Show AbstractWe study the accumulation of positive charge when germanium surface is acted upon by transverse sinusoidal fields. It is shown that the accumulation effect takes place only in the presence of adsorbed water molecules on the surface, and is not observed in the atmosphere of other donor molecules. We develop a donor mechanism for the accumulation effect. We note that the dissociation constant of the adsorbed water molecules depends on the sign of the charge captured into the slow adsorption states.
Show AbstractWe study the M$\stackrel{..}{o}$ssbauer effect in paratellurite monocrystals under hydrostatic pressure up to 30 kbar. We determine the pressure dependence of the probability of the M$\stackrel{..}{o}$ssbauer effect in monocrystals and polycrystals up to 50 kbar. We confirm the presence of a second-order phase transition at pressure 10 kbar above which we observe the disruption of monocrystals.
Show AbstractThe method of Rayleigh scattering of M$\stackrel{..}{o}$ssbauer radiation of $^{57}Co$ is used to measure the elastic-scattering intensity in the (300) and (003) reflections for Те in the temperature range 130-140 K. We determine the root-mean-square displacements of atoms along the [100] and [001] axes.
Show AbstractWe develop an exact formulation of the dynamical theory of diffraction in perfect crystals using new recurrence relations for the amplitude reflection and transmission coefficients obtained by the authors. This formulation contains as an approximation the results of Darwin's dynamical theory. We consider the Bragg (finite and semi-infinite crystals) and Laue cases.
Show AbstractThe pseudopotential method in the nonlocal approximation is used to calculate the band dispersion in strongly anisotropic wide-band crystals $CdI_2$. From the optical reflection spectra obtained using the synchrotron radiation, we calculate the real ($\epsilon _1$) and imaginary ($\epsilon _2$) parts of the dielectric permittivity at T = 77 К by the Kramers-Konig method. We calculate the band structure of the $CdI_2$ crystals and identify the interband optical transitions from the concrete points of the Brillouin zone.
Show AbstractWe study the temperature dependence of the steady-state photoconductivity of undoped films of amorphous hydrogenated silicon for different spectral compositions and intensities of the exciting light. It is observed that the depth of the temperature quenching of photoconductivity is determined by the intensity and energy of a quantum of the exciting light. The observed features agree well with the model of intercenter recombination of charge carriers.
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