13 research outputs found
Uniformly Accelerated Observer in Moyal Spacetime
In Minkowski space, an accelerated reference frame may be defined as one that
is related to an inertial frame by a sequence of instantaneous Lorentz
transformations. Such an accelerated observer sees a causal horizon, and the
quantum vacuum of the inertial observer appears thermal to the accelerated
observer, also known as the Unruh effect. We argue that an accelerating frame
may be similarly defined (i.e. as a sequence of instantaneous Lorentz
transformations) in noncommutative Moyal spacetime, and discuss the twisted
quantum field theory appropriate for such an accelerated observer. Our analysis
shows that there are several new features in the case of noncommutative
spacetime: chiral massless fields in dimensions have a qualitatively
different behavior compared to massive fields. In addition, the vacuum of the
inertial observer is no longer an equilibrium thermal state of the accelerating
observer, and the Bose-Einstein distribution acquires -dependent
corrections.Comment: 19 pages. Typos correcte
Hawking temperature in the eternal BTZ black hole: an example of Holography in AdS spacetime
We review the relation between AdS spacetime in 1+2 dimensions and the BTZ
black hole. Later we show that a ground state in AdS spacetime becomes a
thermal state in the BTZ black hole. We show that this is true in the bulk and
in the boundary of AdS spacetime. The existence of this thermal state is
tantamount to say that the Unruh effect exists in AdS spacetime and becomes the
Hawking effect for an eternal BTZ black hole. In order to make this we use the
correspondence introduced in Algebraic Holography between algebras of
quasi-local observables associated to wedges and doble cones regions in the
bulk of AdS spacetime and its conformal boundary respectively. Also we give the
real scalar quantum field as a concrete heuristic realization of this
formalism.Comment: 29 page
Evaluating Impacts of Deep Oil Spills on Oceanic Marine Mammals
The Deepwater Horizon (DWH) oil spill may be indicative of future large, deep spills that may occur in the coming decades. Given that future deepwater spills are possible, critical considerations include (1) establishing baselines for oceanic marine mammal and populations in at-risk areas, (2) understanding the implications of response choices for oceanic marine mammals, (3) designing studies with adequate coverage for post-spill monitoring, and (4) identifying effective strategies for oceanic marine mammal restoration. In this chapter, we consider these four stages in the context of a series of hypothetical oil spill scenarios, identifying ways that lessons learned from the DWH oil spill and prior events can be applied to future disasters
Black Holes and Thermodynamics: The First Half Century
Black hole thermodynamics emerged from the classical general relativistic
laws of black hole mechanics, summarized by Bardeen-Carter-Hawking, together
with the physical insights by Bekenstein about black hole entropy and the
semi-classical derivation by Hawking of black hole evaporation. The black hole
entropy law inspired the formulation of the holographic principle by 't Hooft
and Susskind, which is famously realized in the gauge/gravity correspondence by
Maldacena, Gubser-Klebanov-Polaykov and Witten within string theory. Moreover,
the microscopic derivation of black hole entropy, pioneered by Strominger-Vafa
within string theory, often serves as a consistency check for putative theories
of quantum gravity. In this book chapter we review these developments over five
decades, starting in the 1960ies.Comment: 31pp + refs, invited contribution to "Quantum Aspects of Black Hole
Physics", Ed. Xavier Calmet (Springer, 2014
The biology and ecology of the ocean sunfish Mola mola: a review of current knowledge and future research perspectives
Relatively little is known about the biology and ecology of the world’s largest (heaviest) bony fish, the ocean sunfish Mola mola, despite its worldwide occurrence in temperate and tropical seas. Studies are now emerging that require many common perceptions about sunfish behaviour and ecology to be re-examined. Indeed, the long-held view that ocean sunfish are an inactive, passively drifting species seems to be entirely misplaced. Technological advances in marine telemetry are revealing distinct behavioural patterns and protracted seasonal movements. Extensive forays by ocean sunfish into the deep ocean have been documented and broad-scale surveys, together with molecular and laboratory based techniques, are addressing the connectivity and trophic role of these animals. These emerging molecular and movement studies suggest that local distinct populations may be prone to depletion through bycatch in commercial fisheries. Rising interest in ocean sunfish, highlighted by the increase in recent publications, warrants a thorough review of the biology and ecology of this species. Here we review the taxonomy, morphology, geography, diet, locomotion, vision, movements, foraging ecology, reproduction and species interactions of M. mola. We present a summary of current conservation issues and suggest methods for addressing fundamental gaps in our knowledge
