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Abstract: One of the main tasks for present and future dark energy surveys is todetermine whether the dark energy is dynamical or not. To illustrate this fromdata, it is commonly used to parameterize the dark energy equation of state was several piecewise constant wis using the principal component analysis PCAmethod over finite redshift bins. We show that there is only $j-1$ freeparameters wis if we choose the redshift as j bins. Without this constrain, oneobtains the inconsistent results from the data analysis. Furthermore, if wdecreases with non-negligible ratio as z does, then PCA fails to reproduce theoriginal behavior of w. Also, time varying w can be confused with the incorrectvalue of constant one when the decreasing or increasing ratio of w is smallbut not negligible.



Author: Seokcheon Lee

Source: https://arxiv.org/



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