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991.
We investigate the geometric phase and dynamic phase of a two-level fermionic system with dispersive interaction, driven by a quantized bosonic field which is simultaneously subjected to parametric amplification. It is found that the geometric phase is induced by a counterpart of the Stark shift. This effect is due to distinct shifts in the field frequency induced by interaction between different states (|e〉 and |g〉 ) and cavity field, and a simple geometric interpretation of this phenomenon is given, which is helpful to understand the natural origin of the geometric phase. 相似文献
992.
Controlling of Slope of Carrier-Envelope Phase of Few-Cycle Laser Pulses on Propagation Distance near the Focus 总被引:1,自引:0,他引:1 下载免费PDF全文
The effect of focusing geometry on slope of carrier-envelope (CE) phase ФCE versus propagation distance from the focus in few-cycle laser pulses is investigated. The slope could be adjusted by changing the distance L between the waist of the incident beam and the lens. At the focus, 偏dФCE/O(Z/ZR) = 0 when L = 0, and 偏dФCE/偏d(z/zR) = -2 when L = ∞. The longer the distance L, the steeper the curve of the CE phase at the focus. 相似文献
993.
A New Method for Calculation of Single Seismic Phase of Cylindrically Multilayered Media Including Liquid Interlayer 下载免费PDF全文
A new method based on generalized reflection and transmission (R/T) coefficients method is proposed to calculate the single seismic phase (SSP) of cylindrically multilayered media including liquid interlayer. The use of normalization factors and normalized Lamé coefficients makes the algorithm stable numerically. Using the modified R/T matrices, we derive the iterative expressions of generalized R/T matrices, and by using the iterative relation we determine the SSP of each interface and the full waveforms. To show the superiority of this new approach for investigating of reflection and transmission properties of cylindrically multilayered media, we simulate the full waveforms and SSPs of cased hole model with annulus I (casing-cement interface) channelling (or, cross-flow). The generalized reflection coefficient spectra and SSPs of interfaces obtained show the propagation mechanism of each component of full waveform clearly. 相似文献
994.
We study phase synchronization in oscillator networks through phase reduced method. The dynamics of networks is reduced to phase equations by this method. Analysing the phase equations through the master stability function method, one obtains that the oscillators with identical frequency can be in-phase synchronized by weak balanced coupling. Similarly, the problem of frequency synchronization of oscillators with different frequencies is transformed to the existence of a locally asymptotically stable equilibrium of the phase error system. 相似文献
995.
Coherent Phase Control of Ultrafast Polarization Beats in Reverse V-Type Three-Level System 下载免费PDF全文
We investigate the third-order nonlinear absorption and dispersion of femto- and atto-second polarization beats between the one-photon degenerate four-wave mixing process and the two-photon nondegenerate four-wave mixing process in the pure homogeneously-broadened reverse V-three-level using twin noisy fields. The third-order nonlinear response can be controlled and modified by the colour-locked correlation of twin noisy fields. Most importantly, the coherent phase control in optical heterodyne detection for studying the phase dispersion of the third-order susceptibility is demonstrated. The radiation-matter detuning oscillation is also considered in the freauencv domain. 相似文献
996.
The transition from stationary to oscillatory states in dynamical systems under phase space compression is investigated. By considering the model for the spatially one-dimensional complex Ginzburg-Landau equation, we find that defect turbulence can be substituted with stationary and oscillatory signals by applying system perturbation and confining variable into various ranges. The transition procedure described by the oscillatory frequency is studied via numerical simulations in detail. 相似文献
997.
Critical Exponents for the Re-entrant Phase Transitions in the Three-Dimensional Blume-Emery-Grifilths Model on the Cellular Automaton 下载免费PDF全文
N. Seferoglu B. Kutlu 《中国物理快报》2007,24(7):2040-2043
The critical behaviour of the three-dimensional Blume-Emery-Griffiths (BEG) model & investigated at D/ J = O, -0.25 and -1 in the range of-1 ≤ K/J ≤ 0 for J -- 100. The simulations are carried out on a simple cubic lattice using the heating algorithm improved from the Creutz cellular automaton (CCA ) under periodic boundary conditions. The universality of the model are obtained for re-entrant and double re-entrant phase transitions which occur at certain D/J and K/J parameters, with J and K representing the nearest-neighbour bilinear and biquadratic interactions, and D being the single-ion anisotropy parameter. The values of static critical exponents β, γ and v are estimated within the framework of the finite-size scaling theory. The results are compatible with the universal Ising critical behaviour for all continuous phase transitions in these ranges. 相似文献
998.
Nonadiabatic Geometric Phase and Induced Persistent Current in Mesoscopic Square Circuit with Tilted Magnetic Field at Edges 下载免费PDF全文
We investigate the geometric phase produced by nonadiabatic transition of spin states at corners of mesoscopic square circuit with tilted magnetic field at its edges, From the Schrodlnger equation, the transitions of electron spin state at corners are described by the transfer matrices. The eigenenergies and eigenstates are obtained from the cyclic condition and the multiplying of the transfer matrices. We show that there exist persistent charge and spin currents in such a system due to the lift of degeneracy between the opposite moving directions in the presence of the tilted magnetic field. The dependences of eigenenergies, geometric phase, charge and spin persistent currents on the tilting angles of magnetic field are analysed. 相似文献
999.
This paper investigates the control role of the relative phase between the probe and driving fields on the gain, dispersion and populations in an open A system with spontaneously generated coherence (SGC). It shows that by adjusting the value of the relative phase, a change from lasing with inversion to lasing without inversion can be realized; the values and frequency spectrum regions of the inversionless gain and dispersion can be obviously varied; high refractive index with zero absorption and electromagnetically induced transparency can be achieved. It is also found that when the driving field is resonant, the shapes of the dispersion and the gain curves versus the probe detuning are very similar if the relative phase of the dispersion lags π/2 than that of the gain, however for the off-resonant driving field the similarity will disappear; the gain, dispersion and populations are periodical functions of the relative phase, the modulation period is always 2π; the contribution of SGC to the inversionless gain and dispersion is much larger than that of the dynamically induced coherence. 相似文献
1000.
Phase transformation and nanograting structure on TiO2 rutile single crystal induced by infrared femtosecond laser 下载免费PDF全文
In this paper, TitaiJum dioxide (TiO2) rutile single crystal was irradiated by infrared femtosecond laser pulses with repetition rate of 250 kHz. For a P-polarized femtosecond laser, the periodic nanograting structure on the ablation crater surface was formed . The periodicity is much less than the laser wavelength. The direction of nanograting alignment depends on the polarization laser beam. Micro-Raman spectra show that the intensity of Eg Raman vibrating mode of rutile phase increases and that of Alg Raman vibrating mode decreases apparently within the ablation crater. With the increase of irradiation time and laser average power, the Raman vibrating modes of anatase phase emerged. Rutile phase of TiO2 single crystal is partly transformed into anatase phase.[第一段] 相似文献