Sahni, Varun2012-03-142012-03-142001-07-05http://hdl.handle.net/11007/1475I describe a new class of quintessence+CDMmodels in which late time scalar field oscillations can give rise to both quintessence and cold dark matter. Additionally, a versatile ansatz for the luminosity dis- tance is used to reconstruct the quintessence equation of state in a model independent manner from observations of high redshift supernovae.enScalar field modelsAccelerating universeArticle