305 citations · 859 across the 25 of their papers we have counts for
13 papers · 1 filter
Gravitational vacuum energy in our recently accelerating universe
Sidney Bludman
We review current observations of the homogeneous cosmological expansion which, because they measure only kinematic variables, cannot determine the dynamics driving the recent acce…
What Drives Our Accelerating Universe?
Sidney Bludman
The homogeneous expansion history H(z) of our universe measures only kinematic variables, but cannot fix the underlying dynamics driving the recent acceleration: cosmographic measu…
Cosmological Acceleration: Dark Energy or Modified Gravity?
Sidney Bludman
We review the evidence for recently accelerating cosmological expansion or "dark energy", either a negative pressure constituent in General Relativity (Dark Energy) or modified gra…
Tracking Quintessence Would Require Two Cosmic Coincidences
Sidney Bludman
Good tracking requires that the quintessence energy fraction slowly increase while the roll slowly decreases, but is not yet truly slow-rolling. The…
What We Already Know About Quintessence
Sidney Bludman
Good tracking requires significant quintessence energy fraction, even in the past, but a potential that is not yet truly slow-rolling. The supernova bound on cosmic acceleration ex…
Observed Smooth Energy Fitted by Parametrized Quintessence
S. A. Bludman
This paper proposes two phenomenological quintessence potentials with parameters fitted to the presently observed ratio $\rat$ of smooth energy to clustered mass and limits on the…
Vacuum Energy: Cosmological Constant or Quintessence?
Sidney Bludman, Matts Roos
For a flat universe presently dominated by smooth energy, either cosmological constant (LCDM) or quintessence (QCDM), we calculate the asymptotic collapsed mass fraction as functio…
Observed Smooth Energy is Anthropically Even More Likely As Quintessence Than As Cosmological Constant
Sidney Bludman
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 f…
Vacuum Energy: If Not Now, Then When?
Sidney A. Bludman
We review the cosmological evidence for a low matter density universe and a cosmological constant or dynamical vacuum energy and address the cosmolog$ coincidence problem: why is t…
Analytic Models for the Mechanical Structure of the Solar Core
Dallas C. Kennedy, Sidney A. Bludman
All stars exhibit universal central behavior in terms of new homology variables (u,w). In terms of these variables, we obtain simple analytic fits to numerical standard solar model…
Variational Principles for Stellar Structure
Dallas C. Kennedy, Sidney A. Bludman
The four equations of stellar structure are reformulated as two alternate pairs of variational principles. Different thermodynamic representations lead to the same hydromechanical…
Cosmological Implications of Two Conflicting Deuterium Abundances
N. Hata, G. Steigman, S. Bludman +1
Constraints on big bang nucleosynthesis (BBN) and on cosmological parameters from conflicting deuterium observations in different high red-shift QSO systems are discussed. The high…
Solar Core Homology, Solar Neutrinos and Helioseismology
Sidney A. Bludman, Dallas C. Kennedy
Precise numerical standard solar models (SSMs) now agree with one another and with helioseismological observations in the convective and outer radiative zones. Nevertheless these m…