Dynamic analysis of assembled structures with nonlinearity

Imperial Users onl

Thermal Tachyon Cosmology

We show that in a multi D\={D} branes system with high temperature, there may exist a thermal cosmological phase before usual tachyon inflation. Though this thermal phase can be very transitory, it may has some interesting applications for early tachyon/brane cosmology.Comment: 5 pages, no figures. new version with 6 pages, part paragraphs were rewritten and title was slightly changed, to publish in PL

On Tachyon Condensation of Intersecting Noncommutative Branes in M(atrix) Theory

The interaction between the intersecting noncommutative D-branes (or membranes) is investigated within the M(atrix) theory. We first evaluate the spectrum of the off-diagonal fluctuation and see that there is a tachyon mode, which signals the instability of the intersecting branes. We next explain in detail how the tachyon modes (which are the off-diagonal fluctuations) can be combined with the original branes (which are the diagonal elements) to become a new diagonal matrix, which then represents the new recombined configurations after the tachyon condensation. The tachyon condensation configurations of the noncommutative branes we find are different from those of the commutative cases studied in the previous literatures.Comment: Latex, 11 pages, typos correcte

Interacting holographic tachyon model of dark energy

We propose a holographic tachyon model of dark energy with interaction between the components of the dark sector. The correspondence between the tachyon field and the holographic dark energy densities allows the reconstruction of the potential and the dynamics of the tachyon scalar field in a flat Friedmann-Robertson-Walker universe. We show that this model can describe the observed accelerated expansion of our universe with a parameter space given by the most recent observational results.Comment: 7 pages, 8 figures, accepted for publication in IJMP

D-brane Dynamics and Creations of Open and Closed Strings after Recommbination

A quantum-mechanical technique is used within the framework of U(2) super-Yang-Mills theory to investigate what happens in the process after recombination of two D-p-branes at one angle. Two types of initial conditions are considered, one of which with $p=4$ is a candidate of inflation mechanism. It is observed that the branes' shapes come to have three extremes due to localization of tachyon condensation. Furthermore, open string pairs connecting the decaying D-branes are shown to be created; most part of the released energy is used to create them. It also strongly suggests that creation of closed strings happens afterward. Closed strings as gravitational radiation from the D-branes are also shown to be created. A few speculations are also given on implications of the above phenomena for an inflation model.Comment: 39pages,Latex,9 eps-figs,in v4 creation of closed strings discussed, energy dissipation by rads. replaced by that by creations of strings; in v5 logic to argue pair-creation of open strings corrected, their number density, energy distribution to them, energy flux of gravi. radiation evaluated quantitatively, 2 intuitive figs.added, 1 initial cond. modified: overlapping -> parallel, refs. on rolling tachyons added;in v6 distribution of the releassed energy corrected:its most part used to created open string pair