Tracking Quintessence Would Require Two Cosmic Coincidences

Good tracking requires that the quintessence energy fraction slowly increase while the roll $\lambda\equiv -d\ln V/\varkappa d\phi$ slowly decreases, but is not yet truly slow-rolling. The supernova bound on the present quintessence equation of state requires either (1) a cosmological constant or other fine-tuned "crawling quintessence" or (2) "roll-over quintessence" that tracked until recently, but now became slow rolling, because of a sharp increase in potential curvature. Thus, fine-tuning is required by constant equation of state and inverse power potentials, but can be avoided by the SUGRA and Skordis-Albrecht potentials and other good trackers, provided quintessence energy domination and slow roll {\em both} began only recently. This makes the time in which we live special in {\em two} respects.Comment: 10 pages, including 2 figures, 3 table

\u3cem\u3ePainting the Map Red: Canada and the South African War, 1899–1902\u3c/em\u3e by Carmen Miller [Review]

Review of Carman Miller, Painting the Map Red: Canada and the South African War, 1899-1902. Montreal: McGill-Queen\u27s University Press, 1993

Knowing the Soviet Union: the ideological dimension

This repository item contains a single article of the Publication Series, papers in areas of particular scholarly interest published from 1989 to 1996 by the Boston University Institute for the Study of Conflict, Ideology, and Policy. The volume this article belongs to is titled "The USSR: what do we know and how do we know it?"

Observed Smooth Energy is Anthropically Even More Likely As Quintessence Than As Cosmological Constant

For a universe presently dominated by static or dynamic vacuum energy, cosmological constant (LCDM) or quintessence (QCDM), we calculate the asymptotic collapsed mass fraction as function of the present ratio of vacuum energy to clustered mass, \Omega_{Q0}/\Omega_{m0}. Identifying these collapsed fractions as anthropic probabilities, we find the value \Omega_{Q0}/\Omega_{m0} \sim 2 to be reasonably likely in LCDM, and very likely in QCDM.Comment: 4 pages, 2 tables, 1 figur