In this letter, we proposed a brand-new version for investigating the optical bistability (OB) and optical multistability (OM) through electron tunneling impact in a defect one-dimensional photonic crystal (1DPC). The defect layer of 1DPC is doped with double quantum dot (DQD) nanostructure which interacts with an indirect incoherent pump and a susceptible probe incident light, respectively. By the usage of the quantum mechanical density matrix method, we first examine the refractive index properties of the defect layer through electron tunneling and indirect incoherent pumping effects. Then, through the usage of the transfer matrix methods, we acquire the reflection and transmission coefficients of the defect 1DPC. At the end, we discuss the OB and OM properties of the reflected and transmitted lighting in negative refractive index situation of the DQD. We determine that during a few parametric conditions the switching from OB to OM or vice versa is feasible for reflected and transmitted light beams.

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Based on two-photon exchange interaction between n coupled optical cavities each of them containing a single three level atom, the n-qubit and n-photonic state transfer is investigated. In fact, following the approach of Ref.[1], we consider n coupled cavities instead of two cavities and generalize the discussions about quantum state transfer, photon transition between cavities and entanglement generations between n atoms. More clearly, by employing the consistency of number of photons (the symmetry of Hamiltonian), the hamiltonian of the system is reduced from 3 n dimensional space into 2n dimensional one. Moreover, by introducing suitable basis for the atom-cavity state space based on Fourier transform, the reduced Hamiltonian is block-diagonalized, with 2 dimensional blocks. Then, the initial state of the system is evolved under the corresponding Hamiltonian and the suitable times T at which the initially unentangled atoms, become maximally entangled, are determined in terms of the hopping strength ξ between cavities.

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