Quintom phase-space: beyond the exponential potential

We investigate the phase-space structure of the quintom dark energy paradigm in the framework of spatially flat and homogeneous universe. Considering arbitrary decoupled potentials, we find certain general conditions under which the phantom dominated solution is late time attractor, generalizing previous results found for the case of exponential potential. Center Manifold Theory is employed to obtain sufficient conditions for the instability of de Sitter solution either with phantom or quintessence potential dominance.Comment: 10 pages, 5 figures. References and a new section added. Minor typos corrected. The current institution of one of the authors has been update

O(\alpha_s) Corrections to Longitudinal Spin-Spin Correlations in e+e- -> q qbar

We calculate the $O(\alpha_s)$ corrections to longitudinal spin-spin correlations in $e^+e^-\to q\bar q$. For top quark pair production the $O(\alpha_s)$ corrections to the longitudinal spin-spin asymmetry amount to less than 1% in the $q^2$-range from above $t\bar t$-treshold up to $\sqrt{q^2}= 1000 GeV$. In the $e^+e^-\to b\bar b$ case the $O(\alpha_s)$ corrections reduce the asymmetry value from its $m=0$ value of -1 to approximately -0.96 for $q^2$-values around the Z-peak. This reduction can be traced to finite anomalous contributions from residual mass effects which survive the $m\to 0$ limit. We discuss the role of the anomalous contributions and the pattern of how they contribute to spin-flip and no-flip terms.Comment: 10 pages, 2 postscript figure

The electrical current effect in phase separated La5/8-yPryCa3/8MnO3: Charge order melting vs. Joule heating

We have studied the effect of electric field on transport properties of the prototypical phase separated manganite La5/8-yPryCa3/8MnO3 with y=0.34. Our results show that the suggested image in which the charge ordered state is melted by the appliance of an electric current and/or voltage has to be revised. We were able to explain the observed resistivity drop in terms of an artifact related to Joule heating and the particular hysteresis that the system under study display, common to many other phase separated manganites.Comment: 2 figures. Accepted in J. Appl. Phy

Libéralisme égalitariste, républicanisme critique et reconnaissance identitaire

In Liberalism’s religion, Laborde defends a liberal egalitarian position and tackles, from a new perspective, some issues dealt with in his republican writings. This article examines some of these issues, paying attention to the place that the recognition of identities occupies both in her republican and in her liberal theories, as well as the type of justification advanced in both cases. The article shows that the recognition of identities has gone from having a peripheral and instrumental role in her republican writings to having a central role in her liberal theory

Francis Fukuyama, Identity: The Demand for Dignity and the Politics of Resentment, New York, Farrar, Straus and Giroux, 2018, 240 pp

En su más reciente ensayo, Francis Fukuyama aborda uno de los temas centrales de la teoría política contemporánea: los desafíos que representan las exigencias de los grupos identitarios para la democracia liberal