Dinda, BikashMaartens, Roy2025-11-062025-11-062025Dinda, B. R. & Maartens, R. (2025) Physical versus phantom dark energy after DESI: thawing quintessence in a curved background. Monthly notices of the Royal Astronomical Society. Letters. [Online] 542 (1), L31–L35.https://doi.org/10.1093/mnrasl/slaf063https://hdl.handle.net/10566/21381Recent data from Dark Energy Spectroscopic Instrument, in combination with other data, provide moderate evidence of dynamical dark energy, w = −1. In the w 0 , w a parametrization of w, there is a preference for a phantom crossing, w < −1, at redshift z ∼ 0 . 5. In general relativity, the phantom equation of state is unphysical. Thus, it is important to check whether phantom crossing is present in other physically self-consistent models of dark energy that have equi v alent e vidence to the w 0 , w a parametrization. We find that thawing quintessence with non-zero cosmic curvature can fit the recent data as well as w 0 , w a in a flat background, based on both parametric and realistic scalar field evolutions. Although the realistic model does not allow w < −1, the parametrizations do allow it. However even if we allow w < −1 the data do not enforce phantom crossing. Thus, the phantom crossing is an artefact of a parametrization that is not based on a physical model.encosmological parametersdark energycosmology: theoryParametrizationphantom crossingArticle