顺磁性物质CeF3中磁化率和费尔德常数的定量计算

本文首先计及晶场对顺磁性物质CeF_3中Ce~(3+)离子4f基态和5d激发态能级的影响,进而考虑了间接交换作用有效场II_v和外磁场H_e共同作用下导致的晶场基态能级的进一步分裂,然后应用基态双能级跃迁模型定量计算了CeF_3中的比法拉第旋转θ_F,费尔德常数F和磁化率X以及它们与温度的依赖关系.计算表明,CeF_3中的磁光效应及其温度特性与Ce~(3+)离子之间的间接交换作用密切相关,在60相似文献   

Solution for One-Dimensional Quantum Oscillator with Time-Dependent Frequency and Mass

Based on the generalized linear quantum transformation theory, we present a normal ordering evolution operator for onedimensional quant urn oscillator with time-dependent frequency and mass, then give the exact expression of the evolution matrix elements, wave function and expectation value of arbitrary observable.     

Quantum mechanical Monte Carlo approach to electron transport at heterointerface

With the progress of LSI technology, the electronic device size is scaled down to the sub 0.1μ m region. In such an ultrasmall device, it is indispensable to take quantum mechanical effects into account in device modeling. In this paper, we present a newly developed quantum Monte Carlo device simulation applicable to ultrasmall semiconductor devices. In this model, the quantum effects are represented in terms of quantum mechanically corrected potential in the classical Boltzmann equation. It is demonstrated that the quantum transport effects such as tunneling and energy quantization in ultrasmall semiconductor devices are obtained for the first time by using the standard Monte Carlo techniques.     

Relativistic field formulation of simultaneous quantum measurement

The simultaneous measurement of Dirac field operators is formulated in analogy to the work of von Neumann and Arthurs-Kelly. Meter fields are coupled to the system field with a relativistically invariant bilinear interaction. Measurement of vacuum meter field expectation values provides for the simultaneous measurement of noncommuting system components. It is shown that two meter coupling allows for a simultaneous minimum in the variance of the subsequent meter measurements. A pseudoscalar self-interaction of the Dirac field is shown to allow simultaneous measurement of positive energy field operators with negative energy meters. The simultaneous measurement ofn noncommuting field operators is obtained by coupling the system ton fermionic fields. Also, in this paper the related concept of mutual simultaneous measurement is developed. This requires that any operators in the enlarged Hilbert space are measurable by the remaining fields as meters. System embedding into a larger Hilbert space results in added noise due to the zero point motion of the meter fields. By the negentropy principle of Brillouin, the added noise is equivalent to entropy. A criterion determining the interaction among fields is that the averaged added noise in the components of each quantum field is minimized. This criterion defines an optimum fermionic mass matrix through the determination of the entangling interaction.1. This work was sponsored by the Department of the Air Force under contract F19628-90-C-0002.     

The Ithaca Interpretation of Quantum Mechanics, and Objective Probabilities

The Ithaca interpretation of quantum mechanics, proposed in 1996 by David Mermin, seeks to reduce the interpretive puzzles of quantum mechanics to the single puzzle of interpreting objective quantum probabilities. Some suggestions are made as to how the numerical values of quantum probabilities could be ontologically based in a world containing all the possible outcomes of all probabilistic processes. It is then shown that Hardy's paradox, discussed by Mermin, can be resolved when probabilities are interpreted in this way.     

Crossed Modules and Quantum Groups in Braided Categories

Let A be a Hopf algebra in a braided category . Crossed modules over A are introduced and studied as objects with both module and comodule structures satisfying a compatibility condition. The category of crossed modules is braided and is a concrete realization of a known general construction of a double or center of a monoidal category. For a quantum braided group the corresponding braided category of modules is identified with a full subcategory in . The connection with cross products is discussed and a suitable cross product in the class of quantum braided groups is built. Majid–Radford theorem, which gives equivalent conditions for an ordinary Hopf algebra to be such a cross product, is generalized to the braided category. Majid's bosonization theorem is also generalized.     

Geometric Analysis and Symbol Calculus: Fourier Transform Magnetic Resonance Imaging and Wavelets

Due to its unequalled advantages, the magnetic resonance imaging (MRI) modality has truly revolutionized the diagnosis and evaluation of pathology. Because many morphological anatomic details that may not be visualized by other high tech imaging methods can now be readily shown by diagnostic MRI, it has already become the standard modality by which all other clinical imaging techniques are measured. The unique quantum physical basis of the MRI modality combined with the imaging capabilities of current computer technology has made this imaging modality a target of interdisciplinary interest for clinicians, physicists, biologists, engineers, and mathematicians. Due to the fact that MRI scanners perform corticomorphic processing, this modality is by far more complex than all the other high tech clinical imaging techniques. The purpose of this paper is to outline a phase coherent wavelet approach to Fourier transform MRI. It is based on distributional harmonic analysis on the Heisenberg nilpotent Lie group G and the associated symplectically invariant symbol calculus of pseudodifferential operators. The contour and contrast resolution of MRI scans which is controlled by symplectic filter bank processing gives the noninvasive MRI modality superiority over X-ray computed tomography (CT) in soft tissue differentiation.     

QUANTUM FLUCTUATIONS IN MESOSCOPIC RESISTANCE-INDUCTANCE-CAPACITANCE ELECTRIC CIRCUITS AT FINITE TEMPERATURE

By using the charge and current in a quantization resistance-inductance-capacitance (RLC) electric circuit, we construct a pair of canonical variables. Using this pair of variables and the thermal field dynamics, we obtain the fluctuations of charge and current in the RLC electric circuit at finite temperatures. It is shown that the fluctuations increase with increasing temperature and decrease with prolonging of time.     

Charged-Exciton Complexes in Quantum Dots

It is known experimentally that stable charged-exciton complexes can exist in low-dimensional semiconductor nanostructures. Much less is known about the properties of such charged-exciton complexes since three-body problems are very difficult to be solved, even numerically. Here we introduce the correlated hyperspherical harmonics as basis functions to solve the hyperangular equation for negatively and positively charged excitons (trions) in a harmonic quantum dot. By using this method, we have calculated the energy spectra of the low-lying states of a charged exciton as a function of the radius of quantum dot. Based on symmetry analysis, the level crossover as the dot radius increases can be fully explained as the results of symmetry constraint.``     

The Spectra of Two-Electron Quantum Dot: Shifted 1/N Method

The spectra of two-electron quantum dot in a magnetic field of arbitrary strength is studied by using the shifted 1/N expansion method. The comparisons show that our results are in good agreement with the results of fixed-phase quantum Monte Carlo method and exact ones [Bolton, Phys. Rev. B54 (1996) 47801.