Lessons from the Andean Community Integration. Jean Monnet/Robert Schuman Paper Series. Vol. 6, No. 12 June 2006

[From the Introduction]. Ever since it was born in the sixties, the Andean Regional Integration Process has attempted to become a strategy to promote a harmonious and balanced development among the Andean Countries. This paper has tree mains goals: (a) To explain and analyse the theoretical concept of the Andean New Regionalism in the framework of Latin American region in a comparative perspective with the European Model of Regional Integration; (b) To show the coexistence of two different regional integration models. Where the dominating one during the sixties was known as old regionalism, and the other that is currently being used is known as new regionalism, and (c) To analyse the way in which this coexistence appears to be an obstacle for the Andean countries to define their regional integration model and to advance toward their main goal: the balanced and harmonious development of each and every country member

Nonlocality and entanglement in qubit systems

Nonlocality and quantum entanglement constitute two special aspects of the quantum correlations existing in quantum systems, which are of paramount importance in quantum-information theory. Traditionally, they have been regarded as identical (equivalent, in fact, for pure two qubit states, that is, {\it Gisin's Theorem}), yet they constitute different resources. Describing nonlocality by means of the violation of several Bell inequalities, we obtain by direct optimization those states of two qubits that maximally violate a Bell inequality, in terms of their degree of mixture as measured by either their participation ratio $R=1/Tr(\rho^2)$ or their maximum eigenvalue $\lambda_{max}$. This optimum value is obtained as well, which coincides with previous results. Comparison with entanglement is performed too. An example of an application is given in the XY model. In this novel approximation, we also concentrate on the nonlocality for linear combinations of pure states of two qubits, providing a closed form for their maximal nonlocality measure. The case of Bell diagonal mixed states of two qubits is also extensively studied. Special attention concerning the connection between nonlocality and entanglement for mixed states of two qubits is paid to the so called maximally entangled mixed states. Additional aspects for the case of two qubits are also described in detail. Since we deal with qubit systems, we will perform an analogous study for three qubits, employing similar tools. Relation between distillability and nonlocality is explored quantitatively for the whole space of states of three qubits. We finally extend our analysis to four qubit systems, where nonlocality for generalized Greenberger-Horne-Zeilinger states of arbitrary number of parties is computed.Comment: 16 pages, 3 figure

The Standard Model instability and the scale of new physics

We apply a general formalism for the improved effective potential with several mass scales to compute the scale M of new physics which is needed to stabilize the Standard Model potential in the presence of a light Higgs. We find, by imposing perturbativity of the new physics, that M can be as large as one order of magnitude higher than the instability scale of the Standard Model. This implies that, with the present lower bounds on the Higgs mass, the new physics could easily (but not necessarily) escape detection in the present and future accelerators.Comment: latex2e, 12 pages, 3 figure

Triple Cohomology of Lie-Rinehart Algebras and the Canonical Class of Associative Algebras

We introduce a bicomplex which computes the triple cohomology of Lie--Rinehart algebras. We prove that the triple cohomology is isomorphic to the Rinehart cohomology \cite{Ri} provided the Lie--Rinehart algebra is projective over the corresponding commutative algebra. As an application we construct a canonical class in the third dimensional cohomology corresponding to an associative algebra

Cooper pair dispersion relation in two dimensions

The Cooper pair binding energy {\it vs.} center-of-mass-momentum dispersion relation for Bose-Einstein condensation studies of superconductivity is found in two dimensions for a renormalized attractive delta interaction. It crosses over smoothly from a linear to a quadratic form as coupling varies from weak to strong.Comment: 2 pages, 1 figure, new version published in Physica