The electric dipole polarizability α_D as a function of the slope of the symmetry energy L for the DD–PC family of functionals and various isotopes. The horizontal shaded regions represent experimental values on α_D: (a) ⁴⁸Ca (J. Birkhan et al. 2017), (b) ⁶⁸Ni (D. M. Rossi et al. 2013), (c) ²⁰⁸Pb (A. Tamii et al. 2011; X. Roca-Maza et al. 2015), (d) ¹²⁰Sn (T. Hashimoto et al. 2015; X. Roca-Maza et al. 2015), and (e)–(j) ^112−124Sn (S. Bassauer et al. 2020).