Shortcuts in the fifth dimension
نویسندگان
چکیده
If our Universe is a three-brane embedded in a five-dimensional antideSitter spacetime, in which matter is confined to the brane and gravity inhabits an infinite bulk space, then the causal propagation of luminous and gravitational signals is in general different. A gravitational signal traveling between two points on the brane can take a “shortcut” through the bulk, and appear quicker than a photon traveling between the same two points along a geodesic on the brane. Similarly, in a given time interval, a gravitational signal can propagate farther than a luminous signal. We quantify this effect, and analyze the impact of these shortcuts through the fifth dimension on cosmology.
منابع مشابه
Dynamics of opinion formation in a small-world network.
The dynamical process of opinion formation within a model using a local majority opinion updating rule is studied numerically in networks with the small-world geometrical property. The network is one in which shortcuts are added to randomly chosen pairs of nodes in an underlying regular lattice. The presence of a small number of shortcuts is found to shorten the time to reach a consensus signif...
متن کاملM ar 2 00 3 Shortcuts in a Dynamical Universe and the Horizon Problem
We consider the dynamics of a FRW brane in a purely AdS background, from the point of view of the bulk, and explicitly construct the geodesical behaviour of gravitational signs leaving and subsequently returning to the brane. In comparison with photons following a geodesic inside the brane, we verify that shortcuts exist, though they are extremely small for today’s Universe. However, we show th...
متن کاملSmall worlds
Small world models are networks consisting of many local links and fewer long range ‘shortcuts’. In this paper, we consider some particular instances, and rigorously investigate the distribution of their inter–point network distances. Our results are framed in terms of approximations, whose accuracy increases with the size of the network. We also give some insight into how the reduction in typi...
متن کاملSpectral dimensions of hierarchical scale-free networks with weighted shortcuts.
Spectral dimensions have been widely used to understand transport properties on regular and fractal lattices. However, they have received little attention with regard to complex networks such as scale-free and small-world networks. Here, we study the spectral dimension and the return-to-origin probability of random walks on hierarchical scale-free networks, which can be either fractal or nonfra...
متن کاملar X iv : 0 71 0 . 25 24 v 1 [ he p - ph ] 1 2 O ct 2 00 7 Neutrino time travel
We discuss causality properties of extra-dimensional theories allowing for effectively superluminal bulk shortcuts. Such shortcuts for sterile neutrinos have been discussed as a solution to the puzzling LSND and MiniBooNE neutrino oscillation results. We focus here on the subcategory of asymmetrically warped brane spacetimes and argue that scenarios with two extra dimensions may allow for timel...
متن کامل