Stability Of Wave Packets Research Articles

Broadband multi-channel quantum noise suppression and phase-sensitive modulation based on entangled beam

We present a theoretical scheme for broadband multi-channel quantum noise suppression and phase-sensitive modulation of continuous variables in a coupled resonant system with quantum entanglement properties. The effects of different coupling strengths, pumping power in suppressing quantum noise and controlling the width of quantum interference channels are analyzed carefully. Furthermore, quantum noise suppression at quadrature amplitude is obtained with phase-sensitive modulation. It shows that the entanglement strength of the output field and the quantum noise suppression effect can be enhanced significantly by a strong pumping filed due to interaction of pumping light with the nonlinear crystal. The full width at half maxima (FWHM) of the noise curve at the resonant peak (Δ = 0 MHz) is broadened up to 2.17 times compared to the single cavity. In the strong coupling resonant system, the FWHM at Δ = 0 MHz (Δ = ±3.1 MHz) is also broadened up to 1.27 (3.53) times compared to the weak coupling resonant system case. The multi-channel quantum interference creates an electromagnetically induced transparent-like line shape, which can be used to improve the transmission efficiency and stability of wave packets in quantum information processing and quantum memory.

Effect of nonextensive electrons on dust–ion acoustic wave self-modulation

Nonlinear self-modulation of dust–ion acoustic (DIA) waves is studied in an unmagnetized dusty plasma comprising warm adiabatic ions, arbitrarily charged dust particles, and hot nonextensive q-distributed electrons. By employing the multiple space and time scales perturbation, a nonlinear Schrödinger equation is derived for the evolution of the wave amplitude. The existence along with the stability of wave packets are discussed in the parameter space of two oppositely charged dust and ion temperature over different ranges of the nonextensive parameter q. The growth rate of the modulation instability is also given for different values of the q parameter. It is found that the critical wave number at which the instability sets in increases as the nonextensive parameter q increases. This leads to a wider range (in spatial extension) of the stable envelope solitons. It is also found that the effects of ion temperature and negative (positive) dust concentration significantly modify the criteria for the modulation instability of DIA waves. Our finding should elucidate the nonlinear electrostatic structures that propagate in astrophysical and cosmological plasma scenarios where nonextensive particles exist: such as instellar plasma, stellar polytropes, cosmic radiation, and systems with long-rang interaction.

Effects of superthermal electrons and negatively (positively) charged dust grains on dust-ion acoustic wave modulation

The modulational instability of dust-ion acoustic (DIA) waves is studied in an unmagnetized dusty plasma comprising arbitrarily charged dust particles, adiabatic fluid ions, and electrons satisfying a kappa (κ) distribution. By using the multiple space and time scales perturbation, a nonlinear Schrodinger (NLS) equation is derived, and then the existence along with the stability of wave packets are discussed in the parameter space of two oppositely charged dust and ion temperature over a range of values of electron superthermality. It is found that the transition from stable dark solitons to unstable bright ones shifts to the smaller wavelength regions in a way that depends on the increase of superthermality index κ. In this case, a narrower range (in spatial extension) of the envelope solitons is observed. It is also found that the instability growth rate reduces, due to the electron superthemality. Furthermore, positive dust concentration enhances the instability region, whereas more populations of negative dust grains may control or suppress one.

Stability of Wave Packets in Layered Hydrodynamic Systems Subjected to the Surface Tension

Stability of Wave Packets in Layered Hydrodynamic Systems Subjected to the Surface Tension