p-brane dynamics in N+1-dimensional FRW universes

• Type: Article in International Scientific Journal
• Date: 2009

Authors

Avelino, PP (Author) FCUP; Menezes, R (Author) Other; Sousa, L (Author) Other

Journal

Title: Physical Review D - Particles, Fields, Gravitation and Cosmology

Vol. 79

ISSN: 1550-7998

Publisher: American Physical Society

Indexing

ISI Web of Knowledge - 6 Citations

Scopus - 6 Citations

Other information

Authenticus ID: P-003-NMV

DOI: 10.1103/physrevd.79.043519

Abstract (EN): We study the evolution of maximally symmetric p-branes with a S(p-i)circle times R(i) topology in flat expanding or collapsing homogeneous and isotropic universes with N+1 dimensions (with N >= 3, p < N, 0 <= i < p). We find the corresponding equations of motion and compute new analytical solutions for the trajectories in phase space. For a constant Hubble parameter H and i=0 we show that all initially static solutions with a physical radius below a certain critical value r(c)(0) are periodic while those with a larger initial radius become frozen in comoving coordinates at late times. We find a stationary solution with constant velocity and physical radius r(c) and compute the root mean square velocity of the periodic p-brane solutions and the corresponding (average) equation of state of the p-brane gas. We also investigate the p-brane dynamics for H not equal constant in models where the evolution of the universe is driven by a perfect fluid with constant equation of state parameter w=P(p)/rho(p) and show that a critical radius r(c) can still be defined for -1 <= w < w(c) with w(c)=(2-N)/N. We further show that for w similar to w(c) the critical radius is given approximately by r(c)H proportional to(w(c)-w)(gamma)(c) with gamma(c)=-1/2 (r(c)H ->infinity when w -> w(c)). Finally, we discuss the impact that the large-scale dynamics of the universe can have on the macroscopic evolution of very small loops.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 6