Comment on ‘Single-mode excited entangled coherent states’
Hong-chun Yuan, Li-yun Hu · Journal of Physics A Mathematical and Theoretical · 2009
In (Xu and Kuang 2006 J. Phys. A: Math. Gen. 39 L191 ), the authors claim that, for single-mode excited entangled coherent states |Ψ ± (α, m )⟩, 'the photon excitations lead to the decrease of the concurrence in the strong field regime of |α| 2 and the concurrence tends to zero when |α| 2 → ∞ '. This is wrong.