Abstract Gibbons and Hawking ( Phys. Rev. D , 15 (1977) 2738) have shown that the horizon of de Sitter space emits radiation in same way as event black hole. But actual cosmological horizons are not horizons, except space. Nevertheless, this paper proves Gibbons' Hawking's formula an exact result for any flat expanding with strictly positive Hubble parameter. The gives visual intuitive insight ...

We study the thermodynamics of de Sitter black holes with a conformally coupled scalar field. The geometry is that of the “lukewarm” Reissner-Nordström-de Sitter black holes, with the event and cosmological horizons at the same temperature. This means that the region between the event and cosmological horizons can form a regular Euclidean instanton. The entropy is modified by the non-minimal co...

We give a general derivation of the gravitational hamiltonian starting from the Einstein-Hilbert action, keeping track of all surface terms. The surface term that arises in the hamiltonian can be taken as the definition of the ‘total energy’, even for spacetimes that are not asymptotically flat. (In the asymptotically flat case, it agrees with the usual ADM energy.) We also discuss the relation...

We examine in an experiment the causes, consequences and possible cures of myopic loss aversion (MLA) for investment behaviour under risk. We find that both, investment horizons and feedback frequency contribute almost equally to the effects of MLA. Longer investment horizons and less frequent feedback lead to higher investments. However, when given the choice, subjects prefer on average shorte...

We derive all the axi-symmetric, vacuum and electrovac extremal isolated horizons. It turns out that for every horizon in this class, the induced metric tensor, the rotation 1-form potential and the pullback of the electromagnetic field necessarily coincide with those induced by the monopolar, extremal Kerr– Newman solution on the event horizon. We also discuss the general case of a symmetric, ...