175 research outputs found

    On the structure of maximal solvable extensions and of Levi extensions of nilpotent algebras

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    We establish an improved upper estimate on dimension of any solvable algebra s with its nilradical isomorphic to a given nilpotent Lie algebra n. Next we consider Levi decomposable algebras with a given nilradical n and investigate restrictions on possible Levi factors originating from the structure of characteristic ideals of n. We present a new perspective on Turkowski's classification of Levi decomposable algebras up to dimension 9.Comment: 21 pages; major revision - one section added, another erased; author's version of the published pape

    All solvable extensions of a class of nilpotent Lie algebras of dimension n and degree of nilpotency n-1

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    We construct all solvable Lie algebras with a specific n-dimensional nilradical n_(n,2) (of degree of nilpotency (n-1) and with an (n-2)-dimensional maximal Abelian ideal). We find that for given n such a solvable algebra is unique up to isomorphisms. Using the method of moving frames we construct a basis for the Casimir invariants of the nilradical n_(n,2). We also construct a basis for the generalized Casimir invariants of its solvable extension s_(n+1) consisting entirely of rational functions of the chosen invariants of the nilradical.Comment: 19 pages; added references, changes mainly in introduction and conclusions, typos corrected; submitted to J. Phys. A, version to be publishe

    Edades radiométricas de los edificios miocenos de Fuerteventura (Islas Canarias).

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    Se han realizado once nuevas dataciones K-Ar de las coladas båsicas (basaltos, nefelinitas) y sålicas (traquitas) de los tres edificios principales subaéreos (Tetir o Norte, Gran Tarajal o Central y Jandía o Sur) que constituyen la Fase miocena de la isla. Se precisa algo mås la cronoestratigrafía relativa entre ellos, así como la correspondiente a los tramos que los integran

    Invariants of solvable rigid Lie algebras up to dimension 8

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    The invariants of all complex solvable rigid Lie algebras up to dimension eight are computed. Moreover we show, for rank one solvable algebras, some criteria to deduce to non-existence of non-trivial invariants or the existence of fundamental sets of invariants formed by rational functions of the Casimir invariants of the associated nilradical.Comment: 16 pages, 7 table

    Rocas volcånicas submarinas en la base de la Formación Cañadas. Macizo de Tigaiga (N. de Tenerife)

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    A volcanic submarine formation crops out in the north coast of Tenerife, east of San Juan de la Rambla. This unit is formed by massive and pil/owed lavas, pillow-breccias, hyaloc/astites and palagonitic tuffs and is interpreted as consisUng of subaerial lavas that flowed into shal/ow marine waters. The lavas are amphibolic trachybasalts. An unaltered sample coming fram the most massive zone has yielded a whole rack 2.60±0.17 Ma K-Ar age. These submarine lavas are underlying the oldest formations of the Las Cañadas Series dated at 1.24 Ma in that same area. The submarine lavas correspond to a time period for which very scarce information was yet available in Tenerife

    Bell-inequalities for K0K0ˉK^0 \bar{K^0} Pairs from Ω\Phi-Resonance Decays

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    We analyze the premises of recent propositions to test local realism via Bell-inequalities using neutral kaons from Ί\Phi-resonance decays as entangled EPR-pairs. We pay special attention to the derivation of Bell-inequalities, or related expressions, for unstable and oscillating kaon `quasi-spin' states and to the possibility of the actual identification of these states through their associated decay modes. We discuss an indirect method to extract probabilities to find these states by combining experimental information with theoretical input. However, we still find inconsistencies in previous derivations of Bell-inequalities. We show that the identification of the quasi-spin states via their associated decay mode does not allow the free choice to perform different tests on them, a property which is crucial to establish the validity of any Bell-inequality in the context of local realism. In view of this we propose a different kind of Bell-inequality in which the free choice or adjustability of the experimental set-up is guaranteed. We also show that the proposed inequalities are violated by quantum mechanics.Comment: 22 pages. Late

    Decoherence of entangled kaons and its connection to entanglement measures

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    We study the time evolution of the entangled kaon system by considering the Liouville - von Neumann equation with an additional term which allows for decoherence. We choose as generators of decoherence the projectors to the 2-particle eigenstates of the Hamiltonian. Then we compare this model with the data of the CPLEAR experiment and find in this way an upper bound on the strength λ\lambda of the decoherence. We also relate λ\lambda to an effective decoherence parameter ζ\zeta considered previously in literature. Finally we discuss our model in the light of different measures of entanglement, i.e. the von Neumann entropy SS, the entanglement of formation EE and the concurrence CC, and we relate the decoherence parameter ζ\zeta to the loss of entanglement: 1−E1 - E.Comment: comments and references added, 18 pages, 1 figur

    Bell inequalities for entangled kaons and their unitary time evolution

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    We investigate Bell inequalities for neutral kaon systems from Phi resonance decay to test local realism versus quantum mechanics. We emphasize the unitary time evolution of the states, that means we also include all decay product states, in contrast to other authors. Only this guarantees the use of the complete Hilbert space. We develop a general formalism for Bell inequalities including both arbitrary "quasi spin" states and different times; finally we analyze Wigner-type inequalities. They contain an additional term, a correction function h, as compared to the spin 1/2 or photon case, which changes considerably the possibility of quantum mechanics to violate the Bell inequality. Examples for special "quasi spin" states are given, especially those which are sensitive to the CP parameters epsilon and epsilon'.Comment: REVTeX, 22 page
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