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Faculty publications – Physics

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Full-Text Articles in Physics

Time Dilation In Relativistic Two-Particle Interactions, B T. Shields, Rainer Grobe, E V. Stefanovich, M R. Ware, Qichang Su, M C. Morris Nov 2010

Time Dilation In Relativistic Two-Particle Interactions, B T. Shields, Rainer Grobe, E V. Stefanovich, M R. Ware, Qichang Su, M C. Morris

Faculty publications – Physics

We study the orbits of two interacting particles described by a fully relativistic classical mechanical Hamiltonian. We use two sets of initial conditions. In the first set (dynamics 1) the system's center of mass is at rest. In the second set (dynamics 2) the center of mass evolves with velocity V. If dynamics 1 is observed from a reference frame moving with velocity-V, the principle of relativity requires that all observables must be identical to those of dynamics 2 seen from the laboratory frame. Our numerical simulations demonstrate that kinematic Lorentz space-time transformations fail to transform particle observables between the …


Unitary And Nonunitary Approaches In Quantum Field Theory, K D. Lamb, Christopher C. Gerry, Rainer Grobe Jan 2007

Unitary And Nonunitary Approaches In Quantum Field Theory, K D. Lamb, Christopher C. Gerry, Rainer Grobe

Faculty publications – Physics

We use a simplified essential state model to compare two quantum field theoretical approaches to study the creation of electron-positron pairs from the vacuum. In the unitary approach the system is characterized by a state with different numbers of particles that is described by occupation numbers and evolves with conserved norm. The nonunitary approach can predict the evolution of wave functions and density operators with a fixed number of particles but time-dependent norms. As an example to illustrate the differences between both approaches, we examine the degree of entanglement for the Klein paradox, which describes the creation of an electron-positron …


Electron-Impact Ionization Of Hydrogen And Lithiumlike Systems, M A. Uddin, Abul Kalam Fazlul Haque, A K. Basak, Khondkar R. Karim, B C. Saha Sep 2005

Electron-Impact Ionization Of Hydrogen And Lithiumlike Systems, M A. Uddin, Abul Kalam Fazlul Haque, A K. Basak, Khondkar R. Karim, B C. Saha

Faculty publications – Physics

The electron impact single ionization cross sections on a number of targets with atomic number Z=1-92 in the H and Li isoelectronic sequences are calculated using a modified version of the recently propounded relativisitic improved binary-encounter dipole (MRIBED) model [M. A. Uddin , Phys. Rev. A 70, 032706 (2004); 71, 032715 (2005)]. The modified RQIBED (MRIBED) model along with a Z-dependent factor in it is found remarkably successful in the applications to H- and Li-like systems and also valid for the ionization of a filled s orbit including the He-like targets.