Maximal Entanglement of Two-qubit States Constructed by Linearly Independent Coherent States

In this paper, we find the necessary and sufficient condition for the maximal entanglement of the state, $ |\psi>=\mu|\alpha>|\beta>+\lambda|\alpha>|\delta>+ \rho|\gamma>|\beta>+\nu|\gamma>|\delta>,$ constructed by linearly independent coherent states with \emph{real parameters} when $<\alpha|\gamma>=<\beta|\delta>$. This is a further generalization of the classified nonorthogonal states discussed in Ref. Physics Letters A {\bf{291}}, 73-76 (2001).