Researchers realize long-lived storage of multimode quantum states

A team led by Prof. has been recently formed. A guiding magnetic field combined with clock state preparation allowed Guo Guangcan to achieve long-lived storage of highdimensional OAM quantum states of photon

Their work was published in a peerreviewed journal. It has been shown that integrating multimode memory into quantum networks can improve channel capacity, which is crucial for long-distance quantum communication.

 It has been shown that integrating multimode memory into quantum networks can improve channel capacity, which is crucial for long-distance quantum communication.

The collective enhancement effect of the cold atomic ensemble allows it to be an efficient medium for storing information.

 many problems remain to be solved in long-lived spatial multimode memory based on cold atomic ensemble and  how to achieve high fidelity for multimode memory after a long storage time since multiple spatial modes

 Based on the degrees of freedom of OAM, the team carried out research on long-lived storage of high-dimensional multimode quantum states using the cold 85Rb system.

 The spatial complexity of stored OAM, the team used a guiding magnetic field to dominate atomic evolution and then used a pair of magnetically sensitive states to suppress the decoherence.

The lifetime of faithful storage was extended when the interference between different Zeeman sublevels was eliminated after the clock states were used.

The team extended the dimensions of stored OAM superposition states to three and achieved fidelity that is two orders of magnitude longer than previous works.

When the storage time was extended from 10μs to 400μs, the retrieval efficiency dropped from 10.7% to 4.7%, showing a clear decreasing trend while the fidelity barely decayed.

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