Remote Entanglement via the Two-Photon Scheme

Yong Hui Yu

Tan Jia, Mao-Fa Fang

We present a scheme to remotely prepare a photon–photon entangled state via entanglement swapping in cavity QED. Using two successive processes of appropriate atom–cavity interaction and subsequent measurements, we obtain the entangled state with certain probability.

Yoon-Ho Kim

Xiao-Lan Zong, Chao-Qun Du, Ming Yang +3 more

We study the entanglement dynamics between two spatially separated atoms trapped in two separate optical cavities. Based on cavity-assisted interactions between the atoms and separated photonic pulses, we propose a scheme for the implemention of a controlled-phase-flip gate (CPF gate) between each of the atoms and the photonic pulse to protect the remote atomic quantum entanglement against the decaying caused by spontaneous emission. What we need to do is to shoot the horizontally polarized photons onto the cavity mirror successively, plus a train of Hadamard operations on the atoms, and no measurement is needed here. It is shown that the quantum entanglement of the two remote atoms can be protected effectively in this way. We also extend our scheme to the case of weak coupling and low Q cavity cases. The simplicity of the current scheme may warrant its experimental realization.

Milena D’Angelo, Alessandro Zavatta, Valentina Parigi +1 more

We propose and experimentally verify a novel method for the remote preparation of entangled bits (ebits) made of a single photon coherently delocalized between two well-separated temporal modes. The proposed scheme represents a remotely tunable source for tailoring arbitrary ebits, whether maximally or non-maximally entangled, which is highly desirable for applications in quantum information technology. The remotely prepared ebit is studied by performing two-mode homodyne tomography with an ultra-fast time-domain balanced homodyne detection scheme recently developed in our laboratory.

Xi Cao, Gangqiang Liu, Tzu-Chiao Chien +3 more