5,515 research outputs found

    Linear Time-Dependent Invariants for Scalar Fields and Noether's Theorem

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    The infinite number of time-dependent linear in field and conjugated momenta invariants is derived for the scalar field using the Noether's theorem procedure.Comment: LaTeX, 6 pages, preprint of Instituto de Ciencias Nucleares, UNAM, Departamento de F\ii sica and Matem\'aticas Aplicadas, M\'exico D. F. , M\'exico No. 04 (1994

    Squeezing in a 2-D generalized oscillator

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    A two-dimensional generalized oscillator with time-dependent parameters is considered to study the two-mode squeezing phenomena. Specific choices of the parameters are used to determine the dispersion matrix and analytic expressions, in terms of standard hermite polynomials, of the wavefunctions and photon distributions. (to be publish in the Third Workshop on Squeezed States and Uncertainty Relations, Baltimore, USA, (August 1993))Comment: LaTeX, 5 pages, preprint of Instituto de Ciencias Nucleares, UNAM Departamento de F\ii sica and Matem\'aticas Aplicadas, No. 02 (1994

    A formula for charmonium suppression

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    In this work a formula for charmonium suppression obtained by Matsui in 1989 is analytically generalized for the case of complex c-cbar potential described by a 3-dimensional and isotropic time-dependent harmonic oscillator (THO). It is suggested that under certain conditions the formula can be applied to describe J/\psi suppression in heavy-ion collisions at CERN-SPS, RHIC, and LHC with the advantage of analytical tractability.Comment: 4 pages, no figures, to appear in Phys. At. Nucl., vol. 7

    Cooling of a suspended nanowire by an AC Josephson current flow

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    We consider a nanoelectromechanical Josephson junction, where a suspended nanowire serves as a superconducting weak link, and show that an applied DC bias voltage an result in suppression of the flexural vibrations of the wire. This cooling effect is achieved through the transfer of vibronic energy quanta first to voltage driven Andreev states and then to extended quasiparticle electronic states. Our analysis, which is performed for a nanowire in the form of a metallic carbon nanotube and in the framework of the density matrix formalism, shows that such self-cooling is possible down to a level where the average occupation number of the lowest flexural vibration mode of the nanowire is 0.1\sim 0.1.Comment: 4 pages, 3 figure

    Policultiu de peixos amb musclos (Mytilus galloprovincialis) a la costa d’Orpesa (Castelló)

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    S’han realitzat proves d’engreix de musclos (Mytilus galloprovincialis Lamarck) suspensos en policultiuamb els peixos d’una granja marina. La presència de la matèria orgànica en suspensió i la major proliferació de microalgues al voltant de les gàbies han afavorit el creixement d’aquestos musclos respecte alscol·locats en dos controls situats a diverses milles al nord de la granja marina, en un cas, i en condicionsde laboratori, en l’altre.Polyculture of mussels (Mytilus galloprovincialis) with some fishes at the Oropesa delMar (Castellón) coast.Mussels (Mytilus galloprovincialis Lamarck) were cultured at a superficial long-line around fish cagesin open sea. The presence of suspended organic matter and the high concentration of microalgae associated with fish cages increase the growth of mussels at the long-line with respect to those grown at a control site located several sea miles northern from the fish farming and at laboratory conditions

    Segal-Bargmann-Fock modules of monogenic functions

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    In this paper we introduce the classical Segal-Bargmann transform starting from the basis of Hermite polynomials and extend it to Clifford algebra-valued functions. Then we apply the results to monogenic functions and prove that the Segal-Bargmann kernel corresponds to the kernel of the Fourier-Borel transform for monogenic functionals. This kernel is also the reproducing kernel for the monogenic Bargmann module.Comment: 11 page

    Entropy-energy inequalities for qudit states

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    We establish a procedure to find the extremal density matrices for any finite Hamiltonian of a qudit system. These extremal density matrices provide an approximate description of the energy spectra of the Hamiltonian. In the case of restricting the extremal density matrices by pure states, we show that the energy spectra of the Hamiltonian is recovered for d=2d=2 and 33. We conjecture that by means of this approach the energy spectra can be recovered for the Hamiltonian of an arbitrary finite qudit system. For a given qudit system Hamiltonian, we find new inequalities connecting the mean value of the Hamiltonian and the entropy of an arbitrary state. We demonstrate that these inequalities take place for both the considered extremal density matrices and generic ones.Comment: 12 pages, 4 figures Accepted for publication in Journal of Physics A: Mathematical and Theoretica
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