1,721,077 research outputs found
Networks of cosmological histories, crossing of the phantom divide line and potentials with cusps.
No full textWe discuss the phenomenon of the smooth dynamical gravity induced crossing of the phantom divide line in a framework of simple cosmological models where it appears to occur rather naturally, provided the potential of the unique scalar field has some kind of cusp. The behavior of cosmological trajectories in the vicinity of the cusp is studied in some detail and a simple mechanical analogy is presented. The phenomenon of certain complementarity between the smoothness of the spacetime geometry and matter equations of motion is elucidated. We introduce a network of cosmological histories and qualitatively describe some of its properties
Perturbation theory of PT-symmetric Hamiltonians
No full textIn the framework of perturbation theory the reality of the perturbed eigenvalues of a class of PT-symmetric Hamiltonians is proved using stability techniques. We apply this method to PT-symmetric unperturbed Hamiltonians perturbed by PT-symmetric additional interactions
Spontaneous PT symmetry breaking in Dirac-Kronig-Penney crystals
No full textSpontaneous PT symmetry breaking in Dirac-Kronig-Penney crystal
Remarks on the general solution for the flat Friedman universe with exponential scalar-field potential and dust
No full textWe show that the simple extension of the method of obtaining the general exact solution for the cosmological model with the exponential scalar-field potential to the case when the dust is present fails and we discuss the reasons of this puzzling phenomenon
Phantom universe from CPT symmetric QFT.
No full textInspired by the generalization of quantum theory for the case of non-Hermitian Hamiltonians with CPT symmetry, we construct a simple classical cosmological scalar field based model describing a smooth transition from ordinary dark energy to the phantom one
Complex Lagrangians and phantom cosmology
No full textMotivated by the generalization of quantum theory for the case of non-Hermitian Hamiltonians with PT symmetry, we show how a classical cosmological model describes a smooth transition from ordinary dark energy to the phantom one. The model is based on a classical complex Lagrangian of a scalar field. Specific symmetry properties analogous to PT in non-Hermitian quantum mechanics lead to purely real equation of motion
Chameleon Cosmology Model Describing the Phantom Divide Line Crossing.
No full textAn exact solution describing the evolution of the type Bang-to-Rip with the phantom divide line crossing is constructed in the Chameleon cosmology model, based on two independent functions of the scalar field
A Search For Exotic T = 2 Or T = 3/2 Meson States At Lear
No full textWe discuss particular ( {Mathematical expression} p) two-body annihilation reactions as a tool to search for exotic meson resonances presumably described in terms of (2q {Mathematical expression}) configurations. These reactions may be studied within the comprehensive program of the OBELIX spectrometer at LEAR
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