After being put into a special device, the safe containing confidential documents can suddenly disappear, and appear in another specific device far away at the same moment, which can be easily taken out. Recently, the new breakthrough in quantum state stealth transmission technology made by the joint team composed of the University of Science and Technology of China and Tsinghua University may make this magical scene of "super time travel" that used to only appear in science fiction movies become a reality.
Sketch Map Professor Peng Chengzhi, a research member of the joint group, introduced that Quantum communication network The core element of quantum state teleportation is a new way of communication, which transmits quantum information carried by quantum state instead of classical information. "In the classical state, each independent photon carries its own information and transmits it through the sending and receiving devices. But in the quantum state, two entangled photons are a group of each other, interrelated, and can disappear mysteriously in one place, without any carrier, and then appear mysteriously in another place. The invisible transmission of quantum state makes use of this characteristic of quantum. First, we split a pair of entangled photons carrying information and send one of them to a specific location. At this time, only the real-time state of one of the photons needs to be known between two places to accurately predict the state of the other photon, So as to achieve a communication mode similar to "super space-time travel". " Peng Chengzhi said.
Quantum teleportation has always been the focus of attention in academia and the public. In 1997, the Austrian Zeilinger team completed the theoretical experimental verification of quantum state teleportation for the first time indoors. In 2004, the team successfully increased the quantum "super space-time travel" distance to 600 meters by using the optical fiber channel at the bottom of the Danube River. However, due to the loss in the fiber channel and the interference of the environment, it is difficult to improve the distance of quantum state teleportation significantly.
In 2004, researchers such as Pan Jianwei and Peng Chengzhi from the University of Science and Technology of China began to explore the realization of quantum communication at a longer distance in free space. In free space, the interference effect of the environment on the quantum states of light is minimal, and once the photon penetrates the atmosphere into outer space, its loss is closer to zero, which makes the free space channel more advantageous than the fiber channel in long-distance transmission.
As early as 2005, the team set a world record of 13 km free space two-way quantum entanglement "splitting" and transmission in Hefei, and verified the feasibility of distributing entangled photons between outer space and the earth. Since 2007, the joint research team of the University of Science and Technology of China and Tsinghua University has set up a free space quantum channel of 16 kilometers in Beijing, and made a series of key technological breakthroughs. Finally, in 2009, it successfully realized the furthest quantum state stealth transmission in the world, which confirmed the feasibility of quantum state stealth transmission through the atmosphere, It has laid a reliable foundation for the future global quantum communication network based on satellite relay.
This achievement has been published in Nature Photonics, a sub journal of the British journal Nature, published on June 1, and has attracted extensive attention from the international academic community.
