Two-center quantum MICZ-Kepler system and the Zeeman effect in the charge-dyon system

The quantum two-center MICZ-Kepler system is considered in the limit when one of the interaction centers is situated at infinity, which leads to homogeneous electric and magnetic fields appearing in the system. The emerging system admits separation of variables in the Schrödinger equation and is integrable at the classical level. The first order corrections to the unperturbed spectrum of the ordinary MICZ-Kepler system are calculated. Particularly, the linear Zeeman effect and effects of MICZ-terms are analyzed. The possible realizations of the system in some quantum dots are considered.     

Synthesis of highly sterically hindered niobium and tantalum alkoxides and their microhydrolysis in strongly basic medium

We have investigated the interaction of niobium and tantalum alkoxides with pinacol and are reporting here isolation and structural characterization of the products, attractive potential precursors of materials with hierarchical porosity. The general feature in the reactivity of alkoxide complexes with additional ligands is that stabilization of the complexes is achieved due to Brønsted acidity of the ligand and possibility of formation of hydrogen bonds in the structure. Presence of strong organic bases does not influence the complex formation. We were able to isolate, for example, highly moisture-sensitive ortho-pinacolates of Nb and Ta, M(O₂C₆H₁₂)₂(OC₆H₁₂OH), in the presence of excess of triethylamine. The earlier attempts to prepare these complexes were unsuccessful because of extremely high solubility and easy hydrolysis of these species. The first step in microhydrolysis of M(O₂C₆H₁₂)₂(OC₆H₁₂OH), M = Nb, Ta, independently of basicity of the medium provides M₂O(O₂C₆H₁₂)₂(OC₆H₁₂OH)₄, even those highly moisture-sensitive in solution. The general conclusion of this work is that the Lewis acidity and blocking of the coordination sites by bulky alkoxide ligands does not play any important role. The reactivity of the species is not in any way hindered by the complete blocking of the metal centers.     

Perturbation of spectra and spectral subspaces

We consider the problem of variation of spectral subspaces for linear self-adjoint operators with emphasis on the case of off-diagonal perturbations. We prove a number of new optimal results on the shift of the spectrum and obtain (sharp) estimates on the norm of the difference of two spectral projections associated with isolated parts of the spectrum of the perturbed and unperturbed operators, respectively.

     

Mössbauer spectroscopy of Co2Mn1 − x Fe x Al

⁵⁷Fe Mössbauer spectroscopic studies of Co₂Mn_1???x Fe _x Al based Heusler compounds are presented. The cubic structure type was found for all samples of the series in XRD studies. However, a mixture of the cubic B2 and L2₁ structure types are not unambiguously distinguished by XRD. The present study gives evidence for a mixture of the L2₁ structure with additions of a large amount of B2 like disorder. The isomer shifts and hyperfine magnetic fields on ⁵⁷Fe atoms are compared with theoretical values from CPA calculations.     

Calculating populations of subcellular compartments using density matrix formalism

In our earlier paper (Ref. 1 ) we developed an integrated probabilistic system for predicting the subcellular localization of proteins and estimating the relative populations of the various compartments in yeast. To justify our formulas we show here that there is a one‐to‐one correspondence between our previous calculations and the prediction of a state of a many‐particle quantum system. The equivalence between these two types of predictions can be easily established if one maps the probability of finding a particular protein in a certain subcellular compartment to the probability of measuring the corresponding quantum particle in one of the possible quantum states (the number of proteins being equal to the number of particles in the system, and the number of compartments being equal to the number of achievable quantum states). Once the sought correspondence is established, we can utilize a well‐known formula from quantum statistical mechanics to calculate the overall occupation of a particular quantum state, associating the state with the corresponding subcellular compartment. In the present work we present the details of how we arrived at the formula for the compartment population, borrowing the tools from quantum statistical mechanics. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001     

CO2 laser-induced micro-plume treatment of silicon: technique and application

Optical and Quantum Electronics - We propose a scheme to realize all-optical temporal differentiation calculation to input pulse in an inverse Y-type four-level atomic system driven by a strong...     

Superluminal light attenuated by strong dispersion of complex refractive index

The propagation of narrow packets of electromagnetic waves(EMWs) in frequency dispersive medium with the consideration of the complex refractive index is studied. It is shown that counting in the dispersion of the complex refractive index within the context of the conventional expression of the group velocity of narrow wave packets of EMWs propagating in a dispersive medium results in the appearance of additional constraints on the group velocity, which dictates that the physically acceptable group velocity can only be realized in the case of a negligible imaginary part of the group index. In this paper, the conditions that allow one to realize the physically acceptable group velocity are formulated and analyzed numerically for the relevant model of the refractive index of a system of two-level atoms in the optical frequency range. It is shown that in the frequency band where superluminal light propagation is expected, there is a strong dispersion of the refractive index that is accompanied with strong absorption, resulting in a strongly attenuated superluminal light.     

Influence of radiation losses on the stability of premixed flames on a porous-plug burner

Analysis of the planar premixed flames on a porous plug was performed numerically for finite activation energy within the diffusive-thermal model. The paper is focused on the influence of radiation heat loses on the flame standoff distance and its linear stability. We show that the presence of volumetric heat losses limits the range of the mass flow range as well as it can promote the flame instabilities of different kinds, both oscillatory and cellular. The oscillatory instability, which for freely propagating flames can be usually observed for the Lewis number larger than one, in the porous-plug case occurs also for flames with unity and lower than unity Lewis number. For flames with Le < 1 both cellular and oscillatory instabilities can be observed simultaneously in a certain range of the mass flow rate.