Bi-metric theory of gravity from the non-chiral Plebanski action

We study a modification of the Plebanski action for general relativity, which leads to a modified theory of gravity with eight degrees of freedom. We show how the action can be recasted as a bi-metric theory of gravity, and expanding around a bi-flat background we identify the six extra degrees of freedom with a second, massive graviton and a scalar mode.Comment: 28 pages. v2 minor typos correcte

Black Hole evaporation in a thermalized final-state projection model

We propose a modified version of the Horowitz-Maldacena final-state boundary condition based upon a matter-radiation thermalization hypothesis on the Black Hole interior, which translates into a particular entangled state with thermal Schmidt coefficients. We investigate the consequences of this proposal for matter entering the horizon, as described by a Canonical density matrix characterized by the matter temperature $T$. The emitted radiation is explicitly calculated and is shown to follow a thermal spectrum with an effective temperature $T_{eff}$. We analyse the evaporation process in the quasi-static approximation, highlighting important differences in the late stages with respect to the usual semiclassical evolution, and calculate the fidelity of the emitted Hawking radiation relative to the infalling matter.Comment: 7 pages, 1 figur

Collective Bargaining under EMU: Lessons from the Italian and Spanish Experiences, CES Working Paper, no. 72, February 2000

This paper seeks to shed light on the question of the likely evolution of collective bargaining in Europe under EMU by considering the experiences of two countries (Italy and Spain) in which governments and social actors attempted to decentralized collective bargaining during the 1980s only to opt in favor of a re-centralization of bargaining during the 1990s. The paper argues that the experiences of Italy and Spain offer two kinds of insights for our understanding of the future evolution of wage bargaining in the EU. On the one hand, they illustrate why governments and social actors may come to favor a consolidation of the structure of bargaining under EMU rather than opt for a further decentralization of bargaining. On the other hand, they also suggest that any such process of consolidation faces great obstacles in moving beyond the national level. The recent experiences of Italy and Spain thus lead us to conclude that the most likely outcome in the EU is that of a reaffirmation of the national and national/sectoral-levels of bargaining within member states, rather than either a radical decentralization of bargaining across the EU, or an effective shift to EU-level bargaining