International Journal of Modern Physics B

The review begins with a consideration of three forms of quantum information entropy associated with Shannon and Jaynes. For model two-electron spin compensated systems, some analytic progress is first reported. The Jaynes entropy is clearly related to correlation kinetic energy. A way of testing the usefulness of a known uncertainty principle inequality is proposed for a whole class of model two-electron atoms with harmonic confinement but variable electron-electron interaction. Emerging properties are then studied by reference to bcc Na at ambient pressure and its modeling by "jellium". Jellium itself has collective behavior with changes of the density, especially noteworthy being the discontinuity of the momentum distribution at the Fermi surface. This has almost reduced to zero at r_s = 100 a.u., the neighborhood in which the quantal Wigner electron solid transition is known to occur. However, various workers have studied crystalline Na under pressure and their results are compared and contrasted. Work by DFT on K, Rb and Cs is discussed, but now with reduced density from the ambient pressure value. The crystalline results for the cohesive energy of these metals as a function of lattice parameters and local coordination number are shown to be closely reproduced by means of ground and excited states for dimer potential energy curves. Then, pair potentials for liquid Na and Be are reviewed, and compared with the results of computer simulations from the experimental structure factor for Na. Finally, magnetic field effects are discussed. First a phenomenological model of the metal-to-insulator transition is presented with an order parameter which is the discontinuity in the Fermi momentum distribution. Lastly, experiments on a two-dimensional electron assembly in a GaAs/AlGaAs heterojunction in a perpendicular magnetic field are briefly reviewed and then interpreted.

A theory for instability in the long-time limit, arising from the electron gyro-motion in strongly magnetized plasmas, is presented. The analysis of the electron motion in the presence of a strong magnetic field leads to a theoretical framework similar to that of the Landau damping. Various electromagnetic modes are predicted to be possibly unstable, and the regime where the radiation from this instability would stand out, compared to the incoherent electron–cyclotron radiation, is identified. This instability would be relevant to the inertial confinement fusion and the gamma ray burst.

Multistep kinetic processes play a key role in physics (excitation transfer, energy degradation), chemistry (ligand–receptor assembly, radical reactions) and biology (signal perception, molecular recognition). While a phenomenological thermodynamic approach for modeling the elementary acts of transitions underlying the maintaining of a system's stationary and equilibrium states is now well recognized, a more satisfying microscopic description based on the consistent understanding of dissipation and fluctuation processes accompanying the multistep relaxations remains elusive. In this paper, a microscopic theory of kinetics of a few-state system exhibited the energy fluctuations and coupled to a condensed medium is developed. The theory is formulated such as of being an example of the case of irreversible multistep ligand–receptor assembly in a dissipating environment. We first derive general expression for the probability of transitions between the system states valid on the whole timescale and then reduce this expression to the effectively slow times by making it an average over both the steady-state fluctuations of a system's energies and the equilibrium vibrations of the environment. Further, we calculate the populations of states for the sequence of cases of the three-to-two-to-single-step assemblage in dependence on the temperature, viscosity and ligand concentration. Finally, we discuss the results obtained with reference to the case of "negative" cooperativity emerging by virtue of the irreversibility of the last kinetic step.

Structural, elastic, electronic and optical properties as well as chemical bonding of the binary alkali metal selenides M₂ Se (M = Li, Na, K, Rb) were calculated using the full potential linearized augmented plane method. From the elastic constants it is inferred that these compounds are brittle in nature. The results of the electronic band structure show that Na₂Se has a direct energy band gap (Γ-Γ), Li₂Se has an indirect energy band gap (Γ- X), while K₂Se and Rb₂Se have an indirect energy band gap (X-Γ). Analysis of the charge distribution plots reveals a dominated ionic bonding in the herein studied compounds. Additionally, we have calculated the optical properties, namely, the real and the imaginary parts of the dielectric function, refractive index, extinction coefficient, optical conductivity and reflectivity for radiation up to 30.0 eV. All these compounds have direct energy band gap greater than 3.1 eV suggesting their use for manufacturing high frequency devices.

In order to study the microstructure of Fe–Ga alloy, Fe₈₅Ga₁₅ ribbons prepared with different wheel velocity were studied by high resolution X-ray diffraction (HRXRD) and extend X-ray absorption fine structure (EXAFS). HRXRD patterns showed that only disordered A₂ phase was observed in as-cast Fe₈₅Ga₁₅ alloy. A modified-DO₃ phase was detected in all of the melt spun samples. The HRXRD associated with EXAFS results indicated that Ga atoms were located as second-nearest neighbor along [100] orientation. A little DO₃ phase was found in ribbons annealed at 1000°C under 0.06 MPa Ar atmosphere. The result of magnetostriction measurement revealed that in the ribbon prepared with higher wheel velocity, more modified-DO₃ phase will enhance the magnetostriction. DO₃ phase in the annealed sample will deteriorate the magnetostrictive properties of Fe–Ga ribbons.

We have developed a spinning polarizer and spinning analyzer (SPSA) method to visualize the whole isochromatic fringes in conoscopic interferometers for the study of optically anisotropic materials. This simple method completely eliminates the broad and dark isogyre fringes appearing in a conventional conoscopic interferometer where a linear polarizer and a linear analyzer (LPLA) are used. Our method allows the direct visualization of the isochromates on the viewing screen by eyes in real time, without the need of additional optics or detectors other than those used in a conventional conoscopic interferometer, and no additional computation is required. This method works at any polarization state of the input light, and at any wavelength permitted by the polarizers. In the case of polychromatic illumination our method reveals the isochromates of all colors indiscriminatively, in comparison to the method of circular polarizer and circular analyzer (CPCA), which is considerably subject to spectrum modulation due to the dispersion in the retardation of the quarter-wave plates. The proposed method is demonstrated in a lithium niobate (LiNbO₃) crystal driven by an external electric field.

We propose a possible way, theoretically, to manipulate a Schrödinger cat state of two degenerate ferromagnetic [FM] ground states of the transverse Ising model [TIM] using macroscopic quantum tunneling (MQT) effect. The MQT process is calculated based on a high-order degenerate perturbative method and can be understood in the language of individual virtual fermions hopping along the spin chain. We present an analytical description of the tunneling process, and discuss experimental feasibility for generating the Cat state in the linear ion trap.

Arsenic-doped HgCdTe usually exhibits compensated n-type conductivity, which is ambiguously attributed to isolated vacancies (V_Hg) or arsenic-vacancy complexes (As_Hg– V_Hg and As_Hg–2V_Hg). Our first-principles calculations clarified the correlation of these V_Hg-related defects with the carrier compensation in As-doped HgCdTe by calculating the defect formation energies, as a function of atomic/electron chemical potentials. Under n-type condition, the lowest formation energy defect is found to be the As_Hg donor followed by the V_Hg acceptor, leading to a compensated n-type material. The arsenic-vacancy complexes are shallow acceptors but their high formation energies render them unlikely to be the compensating candidates. Their large binding energies, however, allow us to predict that the formation of the As_Hg–2V_Hg complex defect will be enhanced under postgrowth annealing treatment, in agreement with the arsenic activation model by Berding et al. [J. Electron. Mater.27, 605 (1998)].

In this paper, a chaotic synchronization scheme is proposed to achieve the generalized synchronization between two different fractional-order chaotic systems. Based on the stability theory of fractional-order systems and the pole placement technique, a controller is designed and theoretical proof is given. Two groups of examples are shown to verify the effectiveness of the proposed scheme, the first one is to realize the generalized synchronization between the fractional-order Chen system and the fractional-order Rössler system, the second one is between the fractional-order Lü system and the fractional-order hyperchaotic Lorenz system. The corresponding numerical simulations verify the effectiveness of the proposed scheme.