Cosmological constant - the weight of the vacuum by T Padmanabhan

By T Padmanabhan

Show description

Read Online or Download Cosmological constant - the weight of the vacuum PDF

Similar cosmology books

Stellar Atmospheres: Theory and Observations

The 1996 summer time institution of the eu Astrophysical Doctoral community handled the atmospheres of stars, many of the theories that describe their constitution and the interactions with the internal of the celebrities in addition to with the interstellar setting, and the observations that aid, adjust and occasionally contradict those theories.

Structures in the Universe by Exact Methods

Because the constructions in our Universe are mapped out on ever better scales, and with expanding aspect, using inhomogeneous types is turning into a vital instrument for interpreting and knowing them. This publication experiences a couple of vital advancements within the program of inhomogeneous options of Einstein's box equations to cosmology.

Star Clusters: Saas-Fee Advanced Course 28. Lecture Notes 1998. Swiss Society for Astrophysics and Astronomy (Saas-Fee Advanced Courses)

Famous person clusters are on the center of astronomy, being key items for our figuring out of stellar evolution and galactic constitution. Observations with the Hubble house Telescope and different smooth gear have published interesting new evidence approximately those galactic construction blocks. This ebook offers entire and updated, pedagogically designed studies on celebrity clusters through famous specialists within the box.

Welcome to the Universe: An Astrophysical Tour

A brand new YORK instances BESTSELLERWelcome to the Universe is a private guided journey of the cosmos via 3 of ultra-modern best astrophysicists. encouraged via the tremendously renowned introductory astronomy path that Neil deGrasse Tyson, Michael A. Strauss, and J. Richard Gott taught jointly at Princeton, this booklet covers it all--from planets, stars, and galaxies to black holes, wormholes, and time go back and forth.

Extra resources for Cosmological constant - the weight of the vacuum

Example text

In both the cases, −1 < w < 1, though it is possible to construct more complicated scalar field Lagrangians with even w < −1. ) Since the quintessence field (or the tachyonic field) has an undetermined free function V (φ), it is possible to choose this function in order to produce a given H(a). ) and ρφ (a) is due to a scalar field. When w(a) is given, one can determine the V (φ) using either (47) or (52). For quintessence, (47) along with (43) gives 3H 2(a) φ˙ 2 (a) = ρ(1 + w) = (1 − Q)(1 + w); 8πG 41 2V (a) = ρ(1 − w) = 3H 2 (a) (1 − Q)(1 − w) 8πG (53) For tachyonic scalar field, (52) along with (43) gives φ˙ 2 (a) = (1 + w); V (a) = ρ(−w)1/2 = 3H 2 (a) (1 − Q)(−w)1/2 8πG (54) Given Q(a), w(a) these equations implicitly determine V (φ).

This means that clusters will be comparatively rare at high redshifts in a ΩNR = 1 universe compared to models with cosmological constant. 5 in a universe with cosmological constant[212,213,214,215,75]. ) Hence the evolution of cluster population as a function of redshift can be used to discriminate between these models. An indirect way of measuring this abundance is through the lensing effect of a cluster of galaxy on extended background sources. Typically, the foreground clusters shears the light distribution of the background object and leads to giant arcs.

The resulting equation is valid in the linear regime and hence will be satisfied by each of the Fourier modes δk (t) obtained by Fourier transforming δ(t, x) with respect to x. Taking δ(t, x) = D(t)f (x), the D(t) satisfies the equation ¨ + 2 a˙ D˙ = 4πGρb D D a (66) The power spectra P (k, t) =< |δk (t)|2 > at two different redshifts in the linear regime are related by P (k, zf ) = T 2 (k, zf , zi , bg)P (k, zi) (67) where T (called transfer function) depends only on the parameters of the background universe (denoted by ‘bg’) but not on the initial power spectrum and can be computed by solving (66).

Download PDF sample

Rated 4.73 of 5 – based on 24 votes