27,791 research outputs found

    (1+1)(1+1) dimensional Dirac equation with non Hermitian interaction

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    We study (1+1)(1+1) dimensional Dirac equation with non Hermitian interactions, but real energies. In particular, we analyze the pseudoscalar and scalar interactions in detail, illustrating our observations with some examples. We also show that the relevant hidden symmetry of the Dirac equation with such an interaction is pseudo supersymmetry.Comment: 9 page

    Scattering states of a particle, with position-dependent mass, in a PT{\cal{PT}} symmetric heterojunction

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    The study of a particle with position-dependent effective mass (pdem), within a double heterojunction is extended into the complex domain --- when the region within the heterojunctions is described by a non Hermitian PT{\cal{PT}} symmetric potential. After obtaining the exact analytical solutions, the reflection and transmission coefficients are calculated, and plotted as a function of the energy. It is observed that at least two of the characteristic features of non Hermitian PT{\cal{PT}} symmetric systems --- viz., left / right asymmetry and anomalous behaviour at spectral singularity, are preserved even in the presence of pdem. The possibility of charge conservation is also discussed.Comment: 12 pages, including 6 figures; Journal of Physics A : Math. Theor. (2012

    The Leggett-Garg inequality and Page-Wootters mechanism

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    Violation of the Leggett-Garg inequality (LGI) implies quantum phenomena. In this light we establish that the Moreva \textit{et al.} \cite{moreva} experiment demonstrating the Page-Wootter's mechanism \cite{wootters} falls in the quantum domain. An observer outside a 2-photons world does not detect any change in the 22-photons state,i.e. there is no time parameter for the outside observer. But an observer attached to one of the photons sees the other photon evolving and this means there is an "internal" time. The LGI is violated for the clock photon whose state evolves with the internal time as measured by the system photon. Conditional probabilities in this 2-photons system are computed for both sharp and unsharp measurements. The conditional probability increases for entangled states as obtained by Page and Wootters for both ideal and also unsharp measurements. We discuss how the conditional probabilities can be used to distinguish between massless and massive gravitons. This is important in the context of gravitational waves.Comment: 5 pages, Late

    On the Laser Stimulation of Low-Energy Nuclear Reactions in Deuterated Palladium

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    Models to account for the observed experimental results for low-energy nuclear reactions in palladium-deuteride systems are presented along with calculated results. The crucial idea is a mechanism of improved probability for the needed penetration of the Coulomb barrier for a D-D reaction. This facilitation occurs, in general, with the formation of D^- ions at special frequency modes (e.g. via phonons) and, specifically for the laser-stimulated case, with utilization of enhanced optical potential at a selected interface. Both mechanisms may work individually, or together, to increase the probability of barrier penetration.Comment: 9 pages, 3 figures, Rev. 1, Significantly enhanced version (resulting from reviewer's comments), Rev. 2, embedded font and smaller file size. Keywords: CMNS, D--D+, LENR, optical-potential, resonance-enhancemen
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