We use a variant of principal component analysis to investigate the possible
temporal evolution of the dark energy equation of state, w(z). We constrain
w(z) in multiple redshift bins, utilizing the most recent data from Type Ia
supernovae, the cosmic microwave background, baryon acoustic oscillations, the
integrated Sachs-Wolfe effect, galaxy clustering, and weak lensing data. Unlike
other recent analyses, we find no significant evidence for evolving dark
energy; the data remains completely consistent with a cosmological constant. We
also study the extent to which the time-evolution of the equation of state
would be constrained by a combination of current- and future-generation
surveys, such as Planck and the Joint Dark Energy Mission.Comment: 6 pages, 5 figure
