One-loop effective brane action

The one-loop effective action for a $p$ brane embedded in a $D=p+2$ Minkowski spacetime in the static gauge is calculated. Rescaling the quantum fluctuation by $\sqrt{-g_0}$ evaluated on the background brane leads to the one-loop effective action expressed only in terms of infrared and ultraviolet divergent geometric scalars. After the infrared divergences are absorbed into the quantum fluctuation, there remains the finite number of ultraviolet divergences. This implies that the $D=p+2$ Poincar\'{e} symmetry and the $D=p+1$ general coordinate invariance are preserved in one-loop order.Comment: 12 pages, no figur

Lovelock black holes surrounded by quintessence

Lovelock gravity consisting of the dimensionally continued Euler densities is a natural generalization of general relativity to higher dimensions such that equations of motion are still second order, and the theory is free of ghosts. A scalar field with a positive potential that yields an accelerating universe has been termed quintessence. We present exact black hole solutions in $D$-dimensional Lovelock gravity surrounded by quintessence matter and also perform a detailed thermodynamical study. Further, we find that the mass, entropy, and temperature of the black hole are corrected due to the quintessence background. In particular, we find that phase transition occurs with divergence of heat capacity at the critical horizon radius, and that specific heat becomes positive for $r_h<r_c$ allowing the black hole to become thermodynamically stable.Comment: 15 pages, 3 figures, accepted for publication in EPJ

Bound information in the environment: Environment learns more than it will reveal

Quantum systems loose their properties due to information leaking into environment. On the other hand, we perceive the outer world through the environment. We show here that there is a gap between what leaks into the environment and what can be extracted from it. We quantify this gap, using the prominent example of the Caldeira-Leggett model, by demonstrating that information extraction is limited by its own lengthscale, called distinguishability length, larger than the celebrated thermal de Broglie wavelength, governing the decoherence. We also introduce a new integral kernel, called Quantum Fisher Information kernel, complementing the well-known dissipation and noise kernels, and show a type of disturbance-information gain trade-off, similar to the famous fluctuation-dissipation relation. Our results show that the destruction of quantum coherences and indirect observations happen at two different scales with a "gray zone" in between. This puts intrinsic limitations on capabilities of indirect observations.Comment: 10 pages, 1 figur