Preparing a GHZ state, or an EPR state, with the one-atom maser

Berthold‐Georg Englert, Nicoletta Sterpi, HERBERT WALTHER

Wang Jun, Longbao Yu, Ye Liu

This paper proposes a simple scheme for generating a three-atom GHZ state via cavity quantum electrodynamics (QED). The task can be achieved through the interaction between two EPR states, which can be prepared easily with current technology. In this scheme, the cavity field is only virtually excited during the interaction process, and no quantum information transfer between the atoms and the cavity is required. Thus it greatly prolongs the efficient decoherent time. Moreover, this scheme is also applicable for generating an N -atom GHZ state.

Han Zhao, Zhou Xiao-Qing, Xiaolin Yang +1 more

We present a scheme for establishing a multi-user quantum channel of multi-atom entangled W states and GHZ states based on cavity QED. Each user has shared EPR pairs with quantum switch during the leisure time of quantum network. An entangled W state is prepared base on two EPR pairs in cavity field by quantum switch at first，and entanglement swapping and direct measurement is operated on the other EPR pairs to establish a quantum channel of W states between three users. In the same way, we can establish a quantum channel of four atoms entangled W state. Three atoms of quantum switch simultaneously interact with cavity field to establish a quantum channel of entangled GHZ states between three users after direct measurement, and we also establish an N users’ quantum channel of entangled GHZ states.

Varcoe

HERBERT WALTHER

Wen-An Li, Lian-Fu Wei

By using quantum Zeno dynamics, we propose a controllable approach to deterministically generate tripartite GHZ states for three atoms trapped in spatially separated cavities. The nearest-neighbored cavities are connected via optical fibers and the atoms trapped in two ends are tunably driven. The generation of the GHZ state can be implemented by only one step manipulation, and the EPR entanglement between the atoms in two ends can be further realized deterministically by Von Neumann measurement on the middle atom. Note that the duration of the quantum Zeno dynamics is controllable by switching on/off the applied external classical drivings and the desirable tripartite GHZ state will no longer evolve once it is generated. The robustness of the proposal is numerically demonstrated by considering various decoherence factors, including atomic spontaneous emissions, cavity decays and fiber photon leakages, etc. Our proposal can be directly generalized to generate multipartite entanglement by still driving the atoms in two ends.