acta physica slovaca

Abstract: The Hamiltonian formulation of relativistic system of pointlike particles with gravitational field is considered within the linearized theory of gravity. Both the Einstein's theory and the gauge theory of gravity are explored. The gauge-invariant description in the terms of Dirac's observables is obtained. Elimination of physical field variables is performed by means of the Dirac's theory of constraints up to the first order in the gravitational constant. The relation between positional and canonical variables of particles is found.

Abstract: We calculate the new physics effects on the anomalous magnetic moment of the muon in the framework of the two Higgs doublet model. We predict an upper bound for the lepton flavor violating coupling, which is responsible for the point like interaction between muon and tau, by using the uncertainty in the experimental result of the muon anomalous magnetic moment. We show that the upper bound predicted is more stringent compared to the one which is obtained by using the experimental result of the muon electric dipole moment.

Abstract: Recently proposed BCS approach with a discretized continuum (by enclosing the nucleus in a spherical box) for the calculation of pairing energy for the drip-line nuclei within the framework of relativistic mean-field (RMF) theory is applied to the description of the ground state properties of Sn isotopes. The TMA parameter set is used for the effective mean-field Lagrangian with the nonlinear terms for the sigma and omega mesons. The results for the two neutron separation energies, and proton and neutron rms radii are shown to be in excellent agreement with the available experimental data and with the recent calculations using the relativistic Hartree-Bogoliubov (RHB) theory. Also, the calculated neutron single particle pairing gaps are found to be in agreement with the RHB and other mean-field calculations.

Abstract: In this communication we analyze the quantum motion of an ion isotropically confined in the radial plane of a Paul microtrap when it is irradiated by a properly chosen configuration of external laser beams. We present a derivation of an analytical solution, by means of which we study the entropic uncertainty relation. Using parameters corresponding to existing experimental realization, we have studied the variation effect for the initial total number of vibrational quanta and the phase.

Abstract: A generalization of the Kronig-Penney problem is put forward with the potential energy $V(x)=\gamma\sum_j{\delta}(x-ja)$, $\gamma>0$. A periodic multi-layer $\dots$ABABABA$\dots$ is considered: layers A of thickness $a$ are intercalated between layers B of much smaller thickness. In this superlattice, A and B symbolize, respectively, narrow-gap semiconductor layers and barrier layers. The conduction band of the semiconductor A is defined by the dispersion function $E({\bf k})$ which was derived in the Kane two-band theory. Owing to the non-zero value of the parameter $\gamma$, the electron energies inside the interval corresponding to the conduction band of the semiconductor A are organized in minibands separated by forbidden gaps. With $E({\bf k})$ taken in the Kane form, the dispersion law ${\cal E}=E({\bf k})$ is non-parabolic if $E_{\rm g}$ (the width of the forbidden gap of the semiconductor A) is finite. This non-parabolicity affects the positions and widths of the minibands. If $E_{\rm g}$ tends to infinity, the original Kronig-Penney problem is recovered. If $E_{\rm g}$ decreases, the density of the minibands increases.

Abstract: In the present communication, we study the influence of phase damping in the presence of Stark shift for the multi-quanta JCM, using a master equation describing phase damping under the Markovian approximation. An analytic solution of the master equation for the multi-quant two-mode JCM Hamiltonian with the phase damping in the presence of Stark shift is obtained. We use this solution to investigate the influence of phase damping and Stark shift on nonclassical properties of the system, for the resonant and the off-resonant cases. We compare the behaviour of the system in the case of having a coherent superposition state and a statistical mixture of coherent states as an initial field. Our results show that the Stark shift plays an important role in the evolution of the population inversion in the JCM.

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