3,241 research outputs found
One-loop effective brane action
The one-loop effective action for a brane embedded in a Minkowski
spacetime in the static gauge is calculated. Rescaling the quantum fluctuation
by 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 Poincar\'{e} symmetry and the 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
-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 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
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