Enhancing entanglement of entangled coherent states via a f-deformed photon-addition operation

Abstract

In this paper, we introduce a new kind of photon-added entangled coherent states (PA-ECSs), by performing repeatedly a f-deformed photon-addition (DPA) operation, $ A^{\dagger}= f(\hat{n}) a^{\dagger}$, on each mode of the entangled coherent states (ECSs), $ \vert\Psi_{\pm}(\alpha)\rangle$. By choosing a particular deformation function $ f(\hat{n})$, we study how the entanglement properties can be enhanced by DPA operation. As a result, we show that both the single and two-mode DPA operation can be used to improve the entanglement of $ \vert\Psi_{+} (\alpha)\rangle$, where the effects of improvement by two-mode DPA operation are more prominent than those by single-mode DPA operation, in any amplitude regime. Moreover, our results show there exists a family of coherent amplitudes $| \alpha |$ such that the two-mode DPA operation preserves the maximal entanglement of the odd ECSs $ \vert\Psi_{-}(\alpha)\rangle$, where the non-deformed photon-addition operation $ a^{\dagger}$ suppresses the entanglement amount. Finally, a theoretical scheme for the physical generation of the introduced states based on a Jaynes-Cummings model with intensity-dependent couplings is proposed.