We consider a picture in which the transition from a big crunch to a big bang corresponds to the collision of two empty orbifold planes approaching each other at a constant non-relativistic speed in a locally flat background space-time, a situation relevant to recently proposed cosmological models. We show that p-brane states which wind around the extra dimension propagate smoothly and unambigu...

We consider quantum field theory on a spacetime representing the Big Crunch/Big Bang transition postulated in ekpyrotic or cyclic cosmologies. We show via several independent methods that an essentially unique matching rule holds connecting the incoming state, in which a single extra dimension shrinks to zero, to the outgoing state in which it re-expands at the same rate. For free fields in our...

a Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089-2535, USA b Perimeter Institute for Theoretical Physics, Waterloo, ON N2L 2Y5, Canada c Department of Physics and School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287-1404, USA d Department of Physics and Princeton Center for Theoretical Physics, Princeton University, Prin...

A well-known clustering algorithm is K-means. This algorithm, besides advantages such as high speed and ease of employment, suffers from the problem of local optima. In order to overcome this problem, a lot of studies have been done in clustering. This paper presents a hybrid Extended Cuckoo Optimization Algorithm (ECOA) and K-means (K), which is called ECOA-K. The COA algorithm has advantages ...

We consider a brane N = I × S0, where S0 is an ndimensional space form, not necessarily compact, in a SchwarzschildAdS(n+2) bulk N and prove that, for specific negative pressures on the brane, the brane is an ARW space. By reflecting N and N to N̂ and N̂ , the joint branes N ∪ N̂ can be naturally embedded as a C∞hypersurface in R2 ×S0, if n is odd and if ω = − n−1 2 is chosen, a value that corresp...