Extracting Closed Classical Orbits from Quantum Recurrence Spectra of a Non-Hydrogenic Atom in Parallel Electric and Magnetic Fields

We show how to extract the closed orbits from the quantum spectra data. According to the closed orbit theory, each closed orbit produces a sharp peak in the recurrence spectra of a non-hydrogenic atom in parallel electric and magnetic fields. For a given initial state, closed-orbit theory gives the dependence of this recurrence amplitude on the initial angle of an orbit. By comparing the recurrence amplitude for different initial states, we can determine the initial angles of the closed classical orbits from the quantum recurrence spectra. Therefore, by integrating the Hamiltonian motion equations, we can obtain the closed orbits directly. This method can also be used to extract the closed orbits from the experimental data.     

Classical Electromagnetic Field Theory in the Presence of Magnetic Sources

Using two new well-defined four-dimensional potential vectors,we formulate the classical Maxwell field theory in a form which has manifest Lorentz covariance and SO(2) duality symmetry in the presence of magnetic sources.We set up a consistent Lagrangian for the theory.Then from the action principle we obtain both Maxwell‘s equation and the equation of motion of a dyon moving in the electromagnetic field.     

Electronic Transport in Nanostructures Consisting of Magnetic—Electric Barriers

We present a theoretical investigation on the transport properties of the nanostructures consisting of magneticelectric barriers produced by the deposition,on the top of a heterostructure,of metallic ferromagnetic stripe with an applied voltage.Both the transmission probability and the conductance are found to be greatly dependent upon the applied voltage.When a positive voltage is applied to the stripe,both the transmission probability and the conductance shift towards low-energy region and increase.Conversely,they move towards high-energy direction and reduce for an applied negative voltage.     

Semiclassical Calculations of Recurrence Spectra for Lithium Atoms in Parallel Electric and Magnetic Fields

By using the region-splitting consistent and iterative method,we calculate the recurrence spectra of lithium atoms in parallel strong external electric and magnetic fields,and obtain the novel resonance structure in the photoabsorption spectrum above the ionization threshold with a constant scaled electric field at F=0.036,and a scaled energy at ε＝0.58 and ε=0.006,respectively.The results are compared with those of hydrogen obtained by using standard closed orbit theory.It is demonstrated that the core-scattered effects exhibited in combination recurrence play a great role.     

Effects of Crossed Electric and Magnetic Fields on Shallow Donor Impurity Binding Energy in a Parabolic Quantum Well

We have calculated variationally the ground state binding energy of a hydrogenic donor impurity in a parabolic quantum well in the presence of crossed electric and magnetic fields. These homogeneous crossed fields are such that the magnetic field is parallel to the heterostructure layers and the electric field is applied perpendicular to the magnetic field. The dependence of the donor impurity binding energy to the well width and the strength of the electric and magnetic fields are discussed. We hope that the obtained results will provide important improvements in device applications, especially for a suitable choice of both fields in the narrow well widths.     

Photodetachment of H- near Elastic Surface in Parallel Electric and Magnetic Fields

The photodetachment cross section of H^- in parallel electric and magnetic fields near an elastic surface is derived and calculated by using the closed orbit theory. It is found that the elastic surface can produce some interesting effects. Besides the closed orbits previously found by Peters et al. for the H^- in parallel electric and magnetic fields, some additional closed orbits are produced due to the effect of the elastic surface. The results show that the cross section oscillation is much more complicated in comparison with the cross section of H^- in parallel external fields without surface. Each peak in the Fourier transformed cross section corresponds to the period of one detached electron closed orbit. This study provides a new understanding of the photodetachment of negative ions in the presence of external fields and surface.     

Magnetic Fields in Active Late—Type Stars

The very high resolution and high signal-to-noise ratio spectra of ten x-ray selected stars are obtained by the NAOC Coude spectropraph.Magnetic field measurements of these stars have been performed using the profileaddition technique.The magnetic field strength and filling factor are obtained,and we find that there exist strong magnetic fields on very active stars.     

A Quantum Theory of Electron Emission from a Metal–Dielectric Structure in High Electric Fields

Technical Physics - A generalized formula for electron emission current as a function of temperature, field, and electron work function in a metal–dielectric system has been derived with...     

Inelastic Electron Transport in Monoatomic Wires

Based on non-equilibrium Green＇s function theory and density functional theory, we investigate the vibrational property and electron-phonon （el-ph） interaction induced inelastic scattering in electron transport through metallic monoatomic wires.     

Current Filamentation and Resonant Transport of the Relativistic Electron Beam in Dense Plasmas

The transport of a relativistic electron beam in dense plasmas with a cold return electron current is examined by two-dimensional particle-in-cell simulation.The filamentation and coalescence of currents and related magnetic field patterns,caused by the electromagnetic-benm-plasma instability,are observed.In the later simulation time,the electrons of the relativistic electron beam are trapped into the potential wells of the wave excited by the instability,and transport resonantly with the wave.     

Electron Acceleration in Collisionless Magnetic Reconnection

A 21/2-dimensional electromagnetic particle-in-cell (PIC) simulation code is used to investigate the electron acceleration in collisionless magnetic reconnection. The results show that the electrons are accelerated in the diffusion region near the X point, and the acceleration process can be roughly divided into two procedures: firstly the electrons are accelerated in the z direction due to the electric field in the negative z direction. Then the electrons gyrate surrounding the magnetic field with the action of the Lorentz force, through this procedure the electrons reach higher velocity in the x direction and then flow out of the diffusion region. After being accelerated away from the diffusion region, part of electrons is trapped near the O point, and the other part of electrons flows into plasma sheet boundary layer along the magnetic field.     

Corrigendum： ＂Extracting Closed Classical Orbits from Quantum Recurrence Spectra of a Non-Hydrogenic Atom in Parallel Electric and Magnetic Fields＂

In a paper published by us,[1] we studied how to extract the closed orbit of the non-hydrogenic atom in parallel electric and magnetic fields. However, there was another paper published in 1996 by Courtney,[2] which studied the initial conditions of closed classical orbits from quantum spectra of hydrogen atom in magnetic field. Although the systems are different, both papers studied a similar problem how to extract tile closed orbits from quantum spectra.     

Electron Transport in Ga-Rich InxGa1-xN Alloys

Resistivity and Hall effect measurements on n-type undoped Ga-rich InxGa1-xN （0.06 ≤ x ≤ 0.135） alloys grown by metal-organic vapour phase epitaxy （MOVPE） technique are carried out as a function of temperature （15-350 K）. Within the experimental error, the electron concentration in Inx Ga1-x N alloys is independent of temperature while the resistivity decreases as the temperature increases. Therefore, Inx Ga1-xN （0.06 ≤ x ≤0.135） alloys are considered in the metallic phase near the Mort transition. It has been shown that the temperaturedependent metallic conductivity can be well explained by the Mort model that takes into account electron-electron interactions and weak localization effects.     

Avron–Herbst Type Formula in Crossed Constant Magnetic and Time-Dependent Electric Fields

In this paper, we give an Avron?CHerbst type formula for the propagator generated by the free Hamiltonian with crossed constant magnetic and time-dependent electric fields. As an application of the formula, we give a result of the existence of the wave operators under some appropriate conditions on the time-dependent electric field and the potential. Finally, in the case where the electric field is time-independent, we consider the problem of the asymptotic completeness of the wave operators.     

Physical Processes of Generating Electric and Magnetic Fields in the Channel of СО2-Laser Pulse Propagation

Russian Physics Journal - Mechanisms of generating electric and magnetic fields during propagation of microsecond CO2-laser pulses in the atmosphere along long paths are considered. The wavelength...     

Magnetic and Transport Properties of ZnO／Co Nanomultilayers

[ZnO(0.5 nm)/Co(0.6 nm)]60 multilayers were fabricated by magnetron sputtering. The magnetic, transport and optical properties were studied. The ferromagnetic state at low temperature was demonstrated. Most of the grains in the samples will be unblocked when temperature is below 50K. The measured magneto-resistance at 4.8K is higher than 30%. This value is larger than any other reported data. The transport mechanism may come down to a combination of tunnelling conduction with the second-order hopping. Some small peaks on transmittance curves were found, the matter is still open.     

Switching Behavior Induced by Electric and Magnetic Fields in （La0.73Bi0.27）0.67Ca0.33MnO3

Both electric and magnetic field-induced switching behaviors between a high resistive state and a low resistive one are observed in （La0.73Bi0.27）0.67Ca0.33MnO3. The effects of magnetoresistance a.nd electric-resistance suggest that the applied electric field and magnetic field greatly tune the percolative paths in the phase-separated system. According to the experimental results, the switching behaviors may come from the coexistence of the charge ordering state, and localized and freedom ferromagnetic states, in which the external field destroys partially the localized ferromagnetic states and charge ordering leads to the ferromagnetic state growth, which causes a switch between a high resistive state and low resistive one. This makes the doped manganite a good system for both electric and magnetic field sensor materials.     

Electronic Transport through a Waveguide in the Presence of a Magnetic Obstacle

By means of the transfer matrix technique, the electronic transport through a quantum waveguide in the presence of a magnetic obstacle is investigated theoretically. By comparing the calculated conductance spectra of the opposite spin electrons, we find that there exists a notable spin filtering window in the low energy region. Dependences of such a spin filtering window on the size, position and potential strength of the magnetic obstacle are studied in detail.     

Blackbody Radiation and the Scaling Symmetry of Relativistic Classical Electron Theory with Classical Electromagnetic Zero-Point Radiation

It is pointed out that relativistic classical electron theory with classical electromagnetic zero-point radiation has a scaling symmetry which is suitable for understanding the equilibrium behavior of classical thermal radiation at a spectrum other than the Rayleigh-Jeans spectrum. In relativistic classical electron theory, the masses of the particles are the only scale-giving parameters associated with mechanics while the action-angle variables are scale invariant. The theory thus separates the interaction of the action variables of matter and radiation from the scale-giving parameters. Due to this separation, classical zero-point radiation is invariant under scattering by the charged particles of relativistic classical electron theory. The basic ideas of the matter-radiation interaction are illustrated in a simple relativistic classical electromagnetic example.     

Resonant Acceleration of Electrons in Combined Self-Consistent Quasistatic Electromagnetic Fields and Intense Laser Fields

Using the single electron model, the acceleration of electrons in combined circularly polarized intense laser fields and the spontaneous quasistatic fields （including axial and azimuthal magnetic fields, the axial and transverse electric fields） produced in intense laser plasma interaction is investigated analytically and numerically by fitting the proper parameters of the quasistatic fields based on the data from the experiment and numerical calculation. A new resonant condition is given. It is found that the resonance acceleration of electron depends not only on laser field, but also on the bounce frequency oscillating in the quasistatic magnetic field and electric field. The net energy gained by electron does not increase monotonously with axial electric field, but there are some optimal axial electric fields.