The well-known self-similar solution for the two-point correlation function of the density field is valid only in an Einstein – de Sitter universe. We attempt to extend the solution for non – Einstein – de Sitter universes. For this purpose we introduce an idea of quasi-self-similar evolution; this approach is based on the assumption that the evolution of the two-point correlation is a successi...

We present a physically reasonable source for an static, axially– symmetric solution to the Einstein equations. Arguments are provided , supporting our belief that the exterior space–time produced by such source, describing a quadrupole correction to the Schwarzschild metric, is particularly suitable (among known solutions of the Weyl family) for discussing the properties of quasi–spherical gra...

We discuss a toy model for an emergent non-relativistic gravitational theory. Within a certain class of Bose–Einstein condensates, it is possible to show that, in a suitable regime, a modified version of non-relativistic Newtonian gravity does effectively describes the low energy dynamics of the coupled system condensate/quasi-particles.

Within a large class of exact solutions of the Einstein equations describing a black hole embedded in a Friedmann universe it is shown that, under certain assumptions, only those with comoving Hawking-Hayward quasi-local mass are generic, in the sense that they are late-time attractors. PACS: 04.70.Bw, 04.20.Jb, 04.50.+h

The Stokes–Einstein relation has long been regarded as one of the hallmarks of transport in liquids. It predicts that the self-diffusion constant D is proportional to (τ/T)−1, where τ is the structural relaxation time and T is the temperature. Here, we present experimental data on water confirming that, below a crossover temperature T× ≈ 290 K, the Stokes– Einstein relation is replaced by a ‘fr...

We study the stability of a quasi-one-dimensional dipolar Bose-Einstein condensate that is perturbed by a weak lattice potential along its axis. Our numerical simulations demonstrate that systems exhibiting a roton-maxon structure destabilize readily when the lattice wavelength equals either half the roton wavelength or a low roton subharmonic. We apply perturbation theory to the Gross-Pitaevsk...

In this paper, we initiate the study of a generalized soliton on Riemannian manifold, find characterization for Euclidean space, and in compact case, sufficient condition under which it reduces to quasi-Einstein manifold. We also conditions an Einstein Note that Ricci solitons being self-similar solutions heat flow, topic is related symmetry geometry manifolds. Moreover, generalizations are nat...

The linear stability of warped product Einstein metrics as fixed points the Ricci flow is investigated. We generalise results Gibbons, Hartnoll and Pope show that in sufficiently low dimensions, all are unstable. By exploiting relationship between metrics, quasi-Einstein solitons, we introduce a new destabilising perturbation (the variation) certain infinite families will be unstable high dimen...

Using effective formulas we analyze the Bose-Einstein correlations (BEC) data corrected for Coulomb interactions provided by STAR Collaboration and the quasi-corrected data on 2π and 3π BEC by using Coulomb wave function with coherence parameter included. The corresponding magnitudes of the interaction regions turn out to be almost the same: R Coul (2π) ≃ 3 2 R Coul (3π). R Coul means the size ...