Transport properties in HTSC materials in the mixed state

Il Nuovo Cimento D - We discuss the resistivity, the Hall, the Seebeck and the Nerst effect in the mixed state taking the motion of Abrikosov and Josephson vortices into account. Measurements on a...     

Operator properties of generalized coherent state systems

The main properties of standard quantum mechanical coherent states and the two generalizations of Klauder and of Perelomov are reviewed. For a system of generalized coherent states in the latter sense, necessary and sufficient conditions for existence of a diagonal coherent stable representation for all Hilbert-Schmidt operators are obtained. The main ingredients are Clebsch-Gordan theory and induced representation theory.     

Laser dye DCM,its spectral properties,synthesis and comparison with other dyes in the red

4-Dicyanomethylene-2-methyl-6-p-dimethylaminostyryl-4H-pyran (DCM) in dimethyl sulfoxide has a broad tuning range and is most efficient dye yet reported for the 630–680 nm region.     

Order of phase transition between the Meissner state and the mixed state

The critical value of the Ginzburg-Landau parameter which separates type-II/1 from type-II/2 superconductors is computed by means of the boson formulation of superconductivity. By taking into account the tail effect of the function c(k), which describes the electrodynamics of the superconducting state, it is shown that the attractive part of the interaction energy between two flux lines indeed vanishes for a critical value of κ. The dependence on Λ = VN(O) is also discussed.     

Microwave dielectric properties of human erythrocyte ghosts in normal and pathological state (Homozygous beta-thalassemia)

Summary The microwave dielectric properties of human normal and homozygous β-thalassemic erythrocyte ghosts have been measured at the frequency of 10 GHz in the temperature interval from 5 to 50 °C. The permittivity and the dielectric loss have been analysed in terms of the Maxwell-Wagner equation for heterogeneous systems. The presence of a remarkable amount of interfacial water at the membrane surface has been evidentiated and some differences in the dielectric parameters of normal and pathological ghosts observed.

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Riassunto Le proprietà dielettriche di sospensioni acquose di ghost derivati da eritrociti umani sia normali che beta-talassemici sono state misurate alla frequenza di 10 GHz modlintervallo di temperatura da 0 a 50°C. I risultati, analizzati sulla base dell'equazion di Maxwell-Wagner per i sistem eterogenei, hanno messo in evidenza la presenza di min notevole quantità di acqua d'idratazione le cui proprietà dielettriche sone state stimate

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Резюме Измеряются микроволновые дизлектрические свойства ?духов? человеческих эритроцитов в нормальном и патологическом состояниях частоте 10 ГГц и в области температур от 5 до 50°C. Анализируются диэлектрическая проницаемость и диэлектрические потери в терминах уравнения Максвелла-Вагнера для гетерогенных систем. Подтверждается наличие заметного количества воды на поверхности мембраны. Обнаружены некоторые различия в диэлектрических параметрах нормальных и патологических ?духов?.

     

Magnetisation of type-II superconductors in the mixed state

The variational method, used in a previous work to study an isolated vortex tube, has been extended to calculate the magnetisation of type-II superconductors for arbitrary values of Ginzburg-Landau parameter κ and over the whole range of the magnetic field from hc₁ to hc₂. The results are discussed.     

Analysis of mixed state entanglement with intrinsic decoherence

We analyze different entanglement measures for a mixed state two-level system in the presence of intrinsic decoherence. The information about entanglement is obtained by comparing the results for the atomic Wehrl entropy and negativity with the analytical results for a simple case. For the strong decoherence case we find that a similar and long-lived maximum Wehrl entropy and negativity between atom and field are shown. The results highlight the important roles played by both the decoherence parameter and the initial state setting in determining the evolution of the atomic Wehrl entropy and negativity.     

Microwave properties of composites with chromium dioxide

The permittivity and permeability of composites filled with CrO₂ powder are measured within the frequency range from 0.05 to 12 GHz. A sharp line of magnetic absorption is detected near 8 GHz. The effects of magnetic bias and remanence on the permittivity and permeability spectra are analyzed. The hysteretic behavior of dynamic permeability is observed for both parallel and perpendicular bias orientations relative to the microwave magnetic field. The effect is due to switching of the magnetic texture under bias equal to coercive field. At 50 MHz the parallel bias close to coercive field affects permeability much stronger than the perpendicular one. At 10 GHz the effect of perpendicular bias is higher than that of the parallel one. The effect of remanence on the microwave permeability is negligible. The 3 kOe parallel bias suppresses the line of magnetic absorption and decreases the conductivity of the composite and its microwave permittivity. This can be attributed to the magnetostatic interaction of inclusions in the vicinity of the percolation threshold.     

Microwave spectra of the ground vibrational state of formaldehyde substituted with O and O

Pure rotational transitions in the ground vibrational state have been measured for H₂¹²C¹⁸O, H₂¹²C¹⁷O, H₂¹³C¹⁸O, and H₂¹³C¹⁷O in the frequency region 8–75 GHz. These have included both Q- and R-branch transitions, and have permitted accurate evaluation of rotational constants and several quartic centrifugal distortion constants for each species. These in turn have permitted the prediction of several transitions of possible use in radioastronomy.