It is impossible to create a practical quantum broadcaster

Sharing quantum information in the same way that we broadcast TV or radio programs can be inaccessible – even for mathematics schemes that surpass the limits created by quantum physics.

We have long known that quantum copy machines can never exist because quantum physics rules forbid any piece of quantum information to be transmitted, it is a cloning theorem called a rule. But then physicians began to find out if they could avoid breaking the law and still distribute copies of quantum information to many recipients.

To do this, researchers will have to allow quantum copies to be slightly different and the recipient’s information information processing measures. Now, Zen Han Liu and his colleagues at Singhwa University in China have shown that these schemes may be prohibited.

“There is no ‘Ctrl+C’ in the world,” says Liu.

Researchers focused on pre -proposed protocols for “virtual quantum broadcasting”, where information is manipulated to connect different states to each other, but they are not direct physical copies of each other. In this case, the message conveyed to every recipient will not be a exact copy, but copies will share enough properties to be useful. This is a comparison with a situation in which a TV network broadcasts a slightly different serialized drama to each home simultaneously, but the average story keeps the same. Although this protocol certainly works, Zhengjing Liu, a member of the team at the National University of Singapore, says researchers wanted to know if it was effective or not.

He estimated how much effort the recipients would have to make the information that reaches them, despite not being the same. Because of this mathematical analysis, they conclude that practical quantum broadcasting cannot exist.

Yun Long Xiao, a member of the team in Science, Technology and Research Agency in Singapore, says that this adaptive version of Quantum Broadcasting approach is also like sending a group text where everyone receives a message at the same time.

“If your sole purpose is to divide quantum states only in different places, I think watching virtual quantum broadcasting is certainly a wrong point of view,” says Sevic Hong Lee, at the Alsan National Institute of Science and Technology in South Korea. That instead of a practical prescription of quantum communication.

Paulo Pirinotti, at the University of Italy, says the team’s job is praiseworthy as a mathematical effort, but also they think quantum technologies are unlikely to have an immediate impact.

Moving forward, researchers are also interested in the ideological lessons of their current analysis. This can help us understand whether the connection – whether it is between quantum states divided into space, or sent one after time over time – allowed and manipulated in it. Xianjing Liu says the work can be part of a new framework to understand the quantum process, which separates less time and space from the traditional point of view.