Beating the channel capacity limit for superdense coding with entangled ququarts
Xiao‐Min Hua b✉, Yu Guoa b✉, Bi‐Heng Liua b✉, Yun‐Feng Huanga b, Chuan‐Feng Lia b✉, Guang‐Can Guoa b
- aChinese Academy of Sciences Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China
- bSynergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China
- ✉Corresponding author
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Abstract
Experimental demonstration of beating the channel capacity limit for superdense coding with high-dimensional entanglement. Quantum superdense coding protocols enhance channel capacity by using shared quantum entanglement between two users. The channel capacity can be as high as 2 when one uses entangled qubits. However, this limit can be surpassed by using high-dimensional entanglement. We report an experiment that exceeds the limit using high-quality entangled ququarts with fidelities up to 0.98, demonstrating a channel capacity of 2.09 ± 0.01. The measured channel capacity is also higher than that obtained when transmitting only one ququart. We use the setup to transmit a five-color image with a fidelity of 0.952. Our experiment shows the great advantage of high-dimensional entanglement and will stimulate research on high-dimensional quantum information processes.
TL;DRThis experiment reports an experiment that exceeds the channel capacity limit for superdense coding with high-dimensional entanglement using high-quality entangled ququarts with fidelities up to 0.98, demonstrating a channel capacity of 2.09 ± 0.01. (Semantic Scholar)

