The ability to create and verify multiparticle entanglement with individual control and measurement of each qubit serves as an important benchmark for quantum technologies. Achieving multi-qubit entanglement requires efficient and precise preparation of quantum states, which has long been the pearl upon the crown in international research.
Recently, the new world record of 18-qubit quantum entanglement with six photons’ three degrees of freedom (6 × 3 = 18) has been achieved by physicists PAN Jianwei, LU Chaoyang, LIU Naile, and WANG Xilin from University of Science and Technology of China of Chinese Academy of Sciences. It surpassed the previous world record of 10-qubit entanglement which was also made by them in 2016.
Researchers developed high-stability interferometers for reversible quantum logic operations between the photons’ different degrees of freedom with precision and efficiencies close to unity, enabling simultaneous readout of 218 = 262,144 outcome combinations of the 18-qubit state. A state fidelity of 0.708 was measured, confirming the genuine entanglement of all 18 qubits.
The successful control over the high-dimensional entanglement will promote the development of quantum information technology with large scale and high efficiency, and is also a key breakthrough for the realization of quantum network in the future.
This study was published as the Editors’ Suggestion in the journal Physical Review Letters.
PAN’s team has been leading the field of quantum entanglement for the past two decades. In 2015, their work on the double quantum-teleportation was selected as the Physics World “Top Breakthrough of the Year”; in 2016, the team contributed to the development of the world’s first quantum satellite Micius, by which the satellite-to-ground level quantum entanglement was demonstrated; in 2017, PAN was named as Nature’s 10 with the label “Father of quantum”.
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