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Abstract
Based on the quantum plasma, the characteristics of the interaction between two planar and nonplanar (cylindrical and spherical) quantum electron acoustic solitary waves (QEASWs) in quantum dense electron-ion plasmas have been studied. The extended Poincaré – Lighthill - Kuo (PLK) method is used to obtain planar and nonplanar analytical phase shifts after the interaction of the two QEASWs. The change of phase shifts and trajectories for QEASWs due to the effect of Bohm potential, the cold electron- to- hot electron number density ratio, Fermi temperature of hot electrons, and the different geometries are discussed. The results show that these parameters have strong effects on the phase shifts and the trajectories of two QEASWs after interaction. For example, the cold electron-to- hot electron number density ratio has an important effect on the dynamical behavior (i.e., rarefactive or compressive) of QEASWs. Furthermore, it has been shown that the interaction of the QEASWs in planar geometry, cylindrical geometry, and spherical geometry are different. Additionally, the head-on collisions between two quantum electrostatic solitary waves (QESWs) in electron-positron-ion quantum plasmas have been investigated using the extended PLK method. The effects of new parameters (e.g., the concentration of hot positrons and Fermi temperature of hot positrons) on the nature of the phase shifts and the trajectories of QESWs in electron- positron- ion quantum plasmas are studied. Numerically, the reported results illustrate that the addition of positron component plays an important role not only on the formations and the dynamical behavior of QESWs but also on the soliton collision. The obtained results are found to be in good agreements with the recorded results. It should be mentioned here that the present study is very useful for the explanation of the collective phenomena and the nature of the solitary collision property in two electron species quantum plasma, which are observed in both of the dense solid state plasma and the dense astrophysical environments.