7,766 research outputs found
Topological Black Holes in Gauss-Bonnet Gravity with conformally invariant Maxwell source
In this paper, we present a class of rotating solutions in Gauss--Bonnet
gravity in the presence of cosmological constant and conformally invariant
Maxwell field and study the effects of the nonlinearity of the Maxwell source
on the properties of the spacetimes. These solutions may be interpret as black
brane solutions with inner and outer event horizons provide that the mass
parameter is greater than an extremal value , an extreme black
brane if and a naked singularity otherwise. We investigate the
conserved and thermodynamics quantities for asymptotically flat and
asymptotically with flat horizon. We also show that the conserved and
thermodynamic quantities of these solutions satisfy the first law of
thermodynamics.Comment: 17 pages, 4 figures, some references adde
Thermodynamics of Quasi-Topological Cosmology
In this paper, we study thermodynamical properties of the apparent horizon in
a universe governed by quasi-topological gravity. Our aim is twofold. First, by
using the variational method we derive the general form of Friedmann equation
in quasi-topological gravity. Then, by applying the first law of thermodynamics
on the apparent horizon, after using the entropy expression associated with the
black hole horizon in quasi-topological gravity, and replacing the horizon
radius, , with the apparent horizon radius, , we derive
the corresponding Friedmann equation in quasi-topological gravity. We find that
these two different approaches yield the same result which show the profound
connection between the first law of thermodynamics and the gravitational field
equations of quasi-topological gravity. We also study the validity of the
generalized second law of thermodynamics in quasi-topological cosmology. We
find that, with the assumption of the local equilibrium hypothesis, the
generalized second law of thermodynamics is fulfilled for the universe
enveloped by the apparent horizon for the late time cosmology.Comment: 8 pages, no figure, Phys. Lett B, in press (2013
Thermodynamics of Rotating Black Branes in Gauss-Bonnet-nonlinear Maxwell Gravity
We consider the Gauss-Bonnet gravity in the presence of a new class of
nonlinear electromagnetic field, namely, power Maxwell invariant. By use of a
suitable transformation, we obtain a class of real rotating solutions with
rotation parameters and investigate some properties of the solutions such as
existence of singularity(ies) and asymptotic behavior of them. Also, we
calculate the finite action, thermodynamic and conserved quantities of the
solutions and using the the Smarr-type formula to check the first law of
thermodynamics.Comment: 15 page
Design of the Artificial: lessons from the biological roots of general intelligence
Our desire and fascination with intelligent machines dates back to the
antiquity's mythical automaton Talos, Aristotle's mode of mechanical thought
(syllogism) and Heron of Alexandria's mechanical machines and automata.
However, the quest for Artificial General Intelligence (AGI) is troubled with
repeated failures of strategies and approaches throughout the history. This
decade has seen a shift in interest towards bio-inspired software and hardware,
with the assumption that such mimicry entails intelligence. Though these steps
are fruitful in certain directions and have advanced automation, their singular
design focus renders them highly inefficient in achieving AGI. Which set of
requirements have to be met in the design of AGI? What are the limits in the
design of the artificial? Here, a careful examination of computation in
biological systems hints that evolutionary tinkering of contextual processing
of information enabled by a hierarchical architecture is the key to build AGI.Comment: Theoretical perspective on AGI (Artificial General Intelligence
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