The modulus fidelity of i-th eigenstates and (i − 1)-th eigenstate in one-dimensional hard-core model. The data are obtained in the site basis and in the condition that 6 bosons on 25 lattices and the next-nearest-neighbor parameters are changed from (a) integrable case to nonintegrable case [panels (b)–(f)]. The dimension of subspace is L = 7085. Average modulus fidelity (g) and the standard deviation of modulus fidelity (h) of neighbor eigenstates in the present model as a function of the next-nearest-neighbor hopping parameters t′ = V′.