For the Shapiro-Wagner-Hradil phase detection description the canonical commutation relation between phase angle ψ and two-mode number-difference operator D = a^†a - b^†b is constructed. Departing from [ψ, D] = -i, the phase angle Hermitian operator is derived in the newly obtained representation < ξ |, where | ξ > is the common eigenket of a + b^† and b + a^†.

Electron interference related to Aharonov-Bohm effect in the presence of the two-mode quantized radiation field is investigated. Characteristics of the temporal behavior of electron interference are discussed. It is shown that for the two-mode squeezed vacuum field the time evolution of the intensity of electron interference can exhibit very interesting periodic spontaneous collapse and revival (CR). In addition, the relation between CR and the quantum fluctuation in electron interference is also discussed.

By factorizing a general one-bit transformation matrix for one-bit gates in quantum computer, a general unitary transformation is constructed, which can serve as (controlled)^m gate for the conditional quantum dynamics. When the quantized single-mode electromagnetic field containing n or no photons acts as the controlled bit, the quantum controlled-NOT gates and square root of the controlled-NOT gates in cavity-quantum electrodynamics are realized.

The aim of the present work is to generalize the method introduced by Güémez et al. [Phys. Rev. E52 (1995) R2145] Using feedback scheme, two systems can be synchronized by signals or variables which come from the driving system. Furthermore, it is possible for the systems to be synchronized by different driving signals which come from the third or fourth system. So the unmasking procedure becomes more difficult. Numerical simulations are given.

The Padé-Z₂ stochastic estimator is used to calculate the fermion matrix determinants and the determinant ratios with an unbiased variational scheme. The results on an 8³ x 12 lattice with Wilson action show that the determinant ratio with a relatively small number of Z₂ noises (e.g., 400) can be estimated by using the unbiased subtractions.

The ground state properties of deformed nuclei of C isotope are investigated by the Skyrme-Hartree-Fock theory with new force parameters SKI4 of Reinhard and Flocard [Nucl. Phys. A 584 (1995) 467]. Calculations show that the deformed-Skyrme-Hartree-Fock theory with above force parameters provides a good description on the binding energy, the various radii and deformation parameters of C isotope. The figure of the evolution of deformation for whole C isotope chain is plotted. A detailed discussion on numerical results is provided in the paper.

The Schrödinger equation of a three-level atom in an electromagnetic wave of circular polarization is established. The solution to this equation shows that under the action of the circular polarized electromagnetic wave, the levels of a Σ-type atom split into nine sublevels, while those of a V-type or Λ-type atom split into six sublevels. By means of some special tuning ways and approximation conditions, the energies of the spilt levels are expressed in simpler forms.

In this paper, a semiclassical approach to trapping problem of atoms in Jaynes-Cummings model is presented. The detuning is expressed by considering detuning as superposition of plenty of harmonic waves. Appearance of trapping atoms is found. On basis of the model, quantum chaos movement of atoms irradiated with strong laser is discussed.

Based on an improved optical system, which consists of six laser diodes with two injection locking stages and control set-ups of the intensity and frequency of the laser, we have achieved the first optical molasses in China. The time-of-flight (TOF) signal of the cloud of Cs atoms has been obtained, and an analytical-formula for measuring the temperature of the atomic cloud from its TOF signal is given. The lowest temperature of the cloud of Cs atoms is measured to be 10μK.

A new analytic model for the above threshold ionization spectrum of He in a circularly polarized laser field is proposed. The experimental spectrum obtained by Mohideen et al. can be quite well described by this model. The spectra predicted by our model agree with experiment better than those of Reiss when the spatiotemporal profile of the laser pulse is taken into account and better than those of the Keldysh-Faisal-Reiss theory when the profile is not taken into account. At the same time, we find that the experimental value of the peak laser intensity was overstated by a factor of about 5. This result supports the previous similar claim by Reiss.

A maximum of 5.5 W of cw TEM₀₀ mode output at 532nm has been obtained by intracavity frequency doubling with a KTP crystal in an Nd: YVO₄ laser doubly-pumped with 20 W diode pumping power. The optical-optical conversion efficiency is 27.5%. The influence of thermal lensing at high pumping power in the end-pumped Nd:YVO₄ laser is discussed. The Nd:YVO₄ laser has a good power stability of 1.6%.

Based on the interference between two two-photon processes, we reported a four-level ultrafast modulation spectroscopy in Na vapor, where 3S, 3P, 5S, and 4D formed a four-level system. We studied the temporal behavior of the four-wave mixing signal intensity and obtained signal modulation with period 25fs, corresponding to the splitting between 5s and 4D. This technique can achieve Doppler-free precision in the measurement of the energy level splitting between two excited states which are dipolar forbidden from the ground state.

A slant grating was recorded with two laser beams incident on photorefractive crystal in an external dc electric field. Two-dimensional perturbative analytical solution for the first two-order space-charge field for steady-state photorefractive slant grating recording has been obtained. It is shown that the inclusion of the longitudinal component of the space-charge field during photorefractive two-wave coupling can predict reduction of the fundamental harmonic and enhancement or reduction of the second-order harmonic for various applied field strength and various grating slant angles. The dependence of the first two-order harmonics on the slant angle and on the applied field strength is examined.

A Thue-Morse optical superlattice made from a single crystal with laminar ferroelectric domain structure was proposed to realize second-harmonic generation. Due to the singular continuous Fourier spectrum in Thue-Morse sequence, this structure shows more plentiful harmonic spectrum, and the intense peaks can be classified according to their different intensity distributions within the superlattice. The harmonic spectra in real space and reciprocal space are presented and discussed.

The responses of the test mass of the new active vibration isolation system incorporating a quasi-fixed reference system to two typical random vibrations such as Gaussian white noise and seismic noise in gravitational experiments are presented. A conclusion is obtained that the isolation performance of the new active vibration isolation system from random vibrations is better than that of the traditional one.

Core and edge turbulences were measured by Langmuir probe arrays in the KT-5C tokamak plasma. The radial wavenumber spectra show a quasimode like structure which results in a net radial outward propagation of the turbulent fluctuations. The measured fluctuation levels and wave action fluxes are in good agreement with model predictions by Mattor et al., suggesting that drift wave propagation could be a source of edge turbulence.

Lower hybrid current drive (LHCD) experiments have been done on the superconducting Tokamak HT-7 by using a new developed long pulse megawatt lower hybrid wave system. An LHCD efficiency of 0.5 x 10¹⁹A.m^-2/W in a pulse length of several hundreds of milliseconds has been achieved. After boronization of the tokamak vacuum vessel, considerable improvements of plasma energy confinement and particle confinement during LHCD phase have been achieved by adjusting wave spectra. An energy transfer from the lower hybrid wave to plasma bulk electrons has been demonstrated experimentally. A computer simulation of the LHCD experiments by using a ray tracing code combined with a two dimensional Fokker-Planck code is in good accordance with experimental measurements and suggests an important role of plasma current profile.

Raman spectra of layered ferroelectrics Ba_2+xBi_4-xTi_5-xNb_xO₁₈ (0 ≤ x ≤ 2) at room temperature in the range 20-1000cm^-1 were investigated. Vibration modes were assigned with the use of internal mode approach. Two doping-induced structure phase transitions were observed at about x = 0.50 and x = 1.25, respectively. Raman spectra variations were analyzed according to the selection rules of BO₆ octahedra in various symmetry. Polycrystalline samples were synthesized by solid state reaction method.

In this study, non-equilibrium statistical physics is used to estimate the time-dependent fracture of inhomogeneous Si₃N₄ ceramic. The effects of structural inhomogeneity on mechanical properties of the Si₃N₄ ceramic are discussed. The numerical calculations show that the average lifetime will increase by means of introducing suitable inhomogeneity in materials, but it is not monotonous.

Using molecular dynamics to simulate MgSiO₃ perovskite is performed to investigate its phase transitions and superionicity. These simulations has used parameter-free Gordon-Kim potentials and a novel technique to monitor the motion of ions which clearly demonstrates the sublattice melting of ions O^2- and the rotations of SiO₆ octahedra. MgSiO₃ has to undergo a few of phase transitions, then enter into the cubic phase. In particular, there is a transitional phase between orthorhombic phase and cubic phase. There are a superionc phase and the cubic phase in magnesium-rich silicate perovskite. This superionic phase occurs after the onset of cubic phase before the melting point. The onset temperature T_c for superionicity is about 200-700K below the melting point T_m, T_c/T_m ~0.92.

Photoconductivity decay (PCD) in semiconductors is investigated by a pulsed laser with an unfocused or a focused beam. The rigorous solutions of PCD under illumination with two different types of laser beams, unfocused and focused, are derived separately. The experimental results of PCD are compared with the theory using Ge-based GaN under illumination of a pulsed Nd:YAG laser at 355nm. The experimental and numerical results are in good agreement.

The effects of flux creep on the magnetization curves of high-temperature superconductors are investigated numerically for Anderson-Kim model. The pinning energy at zero current density, U_c, greatly influences the flux penetration process, a larger U_c, value reults in a larger penetration field. The characteristic of the magnetization curve is also a function of U_c. The magnetization M and ΔM increase with the increasing U_c and depend on the magnetic induction B, so the critical current formula based on Bean model is pot accurate, especially for high-T_c superconductor, for which flux creep is a large effect.

An analytical expression of free induction decay has been derived for calculating the magic angle spinning sideband patterns of nuclear magnetic resonance spectra in a two-site exchange problem. The expression has been confirmed by comparing the calculated spinning sideband patterns for powdered crystalline dimethyl sulfone at different exchange rates with experimentally measured spectra at various temperatures.

Experimental results are given for the temperature dependence of the decay time of the emission at 430nm from PbWO₄ crystal under vacuum-ultraviolet (82nm) photon excitation in the temperature range of 80-300K. The structures in the curve are interpreted for the first time by studying the thermoluminescence of PbWO₄, which originates from the traps in the crystal.

The cathodoluminescence of ZnO films deposited on Si substrates by reactive dc sputtering is investigated. Apart from the characteristic green emission band (522nm) of ZnO, an ultraviolet (392nm) band and a blue (430-460 nm) band have been observed. The x-ray diffraction and cathodoluminescent spectra reveal the dependences of the luminescence on the preparation conditions and crystallinity of the ZnO films.

The oriented heteroepitaxial diamond films were obtained on Si(100) substrate via electron emission in hot filament chemical vapor deposition with the orientation relationship of diamond < 100 >//Si< 100 > and < 110 > //Si< 110 >. The nucleation and subsequent growth of diamond films were characterized by scanning electron microscopy and Raman spectroscopy. The experimental results showed that the electron emission from the diamond coating on the electrode played a critical role during the nucleation due to excition plasma. The maximum value of nucleation density was up to 10¹¹cm^-2 on pristine Si surface at emission current of 250mA. The effect of the electron emission on the reactive gas composition was analyzed by in situ infrared absorption, indicating that the concentration of CH₄ and C₂H₂ near the substrate surface was extremely increased. This may be responsible for the enhanced nucleation by electron emission.

Synchronous oscillation with frequencies in γ band (30-70 Hz), regarded as relevant to the information processing such as scene segmentation, has been numerically studied in a neuronal network. It is found that this synchronous oscillation relates to an intrinsic oscillation of the system in γ band and this feature is robust to various configurations of external stimuli and couplings.

On the basis of photogravitational theory, the influence of solar photogravitation on the motion of comet Hale-Bopp is discussed. It is shown that for plasma tail of comet Hale-Bopp there is only one collinear point L₃ and for a few of dust tail there can be two coplanar points L₆, L₇ and three collinear points L₂₁, L₂₂, L₃. The regions in which the coplanar points exist and the dust grain of comet Hale-Bopp can move are also obtained.