Entangled-state generation via light-induced atom-atom interaction

Lin Li, Yaroslav O. Dudin, A. Kuzmich

Zeyang Li, Boris Braverman, Simone Colombo +6 more

The interaction between an atomic ensemble and a light mode in a high-finesse optical cavity can easily reach the strong-coupling regime, where quantum effects dominate.In this regime, the interaction can be used to generate both atom-light and atom-atom entanglement.We analyze the dominant effects on the collective atomic state and the light field, and derive a unified approach that can account for atomic entanglement induced both by measurements on the light field, and by ignoring the state of the light field altogether.We present analytical expressions for the entanglement induced by the interaction, and determine the conditions that maximize the entanglement-induced gain over the standard quantum limit in quantum sensors and atomic clocks.

Y. Li, Yefeng Mei, Huy Minh Nguyen +2 more

The authors study the dynamics of dephasing induced by Rydberg-Rydberg interactions and show that, as a result of these interactions, an initially unentangled Rydberg spin wave evolves into an entangled Dicke state. The results of this study have relevance to broad classes of applications for collective atomic systems, including driving of collective atomic qubits, on-demand generation of single photons, and preparation of entangled states involving atoms or light.

NASSER METWALLY, Mahmoud Abdel‐Aty, A.‐S. F. Obada

Chen, Zhihua, Lin - +1 more

Shuai Gao, Ebubechukwu O. Ilo-Okeke, Yuping Mao +4 more

Abstract We study the robustness of quantum nondemolition (QND) measurement induced entanglement between Bose–Einstein condensates (BECs). We consider an experimental scheme where two BECs are placed in the paths of a Mach–Zehnder interferometer, and a QND interaction creates entanglement between coherent light and the atoms. We analyze the two dominant channels of decoherence, atomic dephasing and photon loss on the entangled states produced by this scheme. We calculate the effect of dephasing on the variance and expectation values of the spin operators, entanglement and correlation criteria. Our analysis does not use the Holstein–Primakoff approximation, and is capable of modelling long light–atom interaction times, producing non-Gaussian states beyond the two-mode squeezed states. In the presence of dephasing, the entangled states are robust in the macroscopic limit as long as the dimensionless interaction time is less than 1 / N , where N is the number of atoms in the BEC. For photon loss, the entangled states generated by long interaction times show a remarkable robustness that makes the scheme promising for various quantum information applications.