Abstract
It is crucial for the physical realization of quantum information networks to first establish entanglement among multiple space-separated quantum memories and then, at a user-controlled moment, to transfer the stored entanglement to quantum channels for distribution and conveyance of information. Here we present an experimental demonstration on generation, storage, and transfer of deterministic quantum entanglement among three spatially separated atomic ensembles. The off-line prepared multipartite entanglement of optical modes is mapped into three distant atomic ensembles to establish entanglement of atomic spin waves via electromagnetically induced transparency light–matter interaction. Then the stored atomic entanglement is transferred into a tripartite quadrature entangled state of light, which is space-separated and can be dynamically allocated to three quantum channels for conveying quantum information. The existence of entanglement among three released optical modes verifies that the system has the capacity to preserve multipartite entanglement. The presented protocol can be directly extended to larger quantum networks with more nodes.
Highlights
It is crucial for the physical realization of quantum information networks to first establish entanglement among multiple space-separated quantum memories and at a user-controlled moment, to transfer the stored entanglement to quantum channels for distribution and conveyance of information
In 2010, Kimble’s group demonstrated measurement-induced entanglement stored in four atomic memories and coherent transfer of the atomic entanglement to four photonic channels[28]. Their experiment proved that a multipartite entangled W state of atomic ensembles can be transferred into a photonic mode W state with the heralded entanglement and showed an advance in the distribution of multipartite entanglement across quantum networks
Three space separated submodes ^að0ÞS1, ^að0ÞS2; and ^að0ÞS3 of an optical entangled state off-line prepared in Part I interact, respectively, with three atomic memories A1, A2, and A3 located at three distant nodes to generate and store entanglement of spin waves among three atomic ensembles
Summary
It is crucial for the physical realization of quantum information networks to first establish entanglement among multiple space-separated quantum memories and at a user-controlled moment, to transfer the stored entanglement to quantum channels for distribution and conveyance of information. We present an experimental demonstration on generation, storage, and transfer of deterministic quantum entanglement among three spatially separated atomic ensembles. A narrow band optical cavity can be utilized for separating these optical modes, entanglement among them will be significantly reduced[36] These limitations make difficult to extend the experimental method of ref. After a given storage time, the preserved atomic entanglement is controllably released into three separated quantum channels consisting of three entangled optical submodes. The presented scheme can be directly extended to generate optical entangled states with more submodes if more squeezed states of light are available. In this way, entanglement of more atomic ensembles can be established
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
