It is impossible to build a practical quantum form

Sharing quantum information in the same way that we publish TV or radio programs can be impressed – even for mathematical schemes that separate the limitations of quantum physics.

We have long known that quantum copy copy could never exist the laws of quantum physics prohibit a piece of quantum information being duplicated, a rule called theorem without cloning. But then physicists began to explore where they could break this law and still distribute – or send out – copies of quantum information to many recipients.

To do this, researchers would have to allow quantum copies to deviate a little and add new information processing steps to the recipients. Now Zhenhuan Liu at Tsinghua University in China and his colleagues has shown that these schemes can be impractical.

“There is no ‘Ctrl+C’ in the quantum world,” says Liu. “If you want to send quantum information to multiple recipients, there are Na -Effective Shortcut – you easily need to prepare enough copies and send each of them.”

The researchers focused on a previously suggested protocol for “virtual quantum broadcast”, where information is manipulated so that different states are corrected with each other but are not direct physical replicas of another. In this case, the message delivered to each recipient would be an exact copy, but the copies weld enough to be used. It can be compared to a situation where a TV network simultaneously emits a slightly different serialized drama for each household, but holds the story on average the same. Although this protocol certainly certainly, team member Xiangjing Liu says at the National University of Singapore, researchers wanted to know if it is effective.

They quantified how much effort receives to review the information that reaches them to be used, despite not being identical. This mathematical analysis led them to conclude that practical quantum emergence maybe just not.

Probably, even this fine -tuned version of the quantum broadcast method – related to sending a group text where everyone receives a message at once – would require more resources than a technique more like writing a person to anyone’s recipient from scratch, says team member Yunlong Xiao at the Agency for Science, Technology and Research in Singapore.

“If your only goal simply distributes quantum states to different places, I think looking at the virtual quantum broadcast is definitely a wrong approach,” says Seok Hyung at the Ulsan National Institute of Science and Technology in South Korea. He says the protocol had always been conceived as a study of the basic restrictions on processes in Quanttum Information Theory, rather than a practical recipe for quantum communication.

Paolo Perinotti at the University of Pavia in Italy says the team’s work is commendable as a mathematical effort, but also that he thinks it is unlikely to have an immediate influence on quantum technologies.

In the future, the researchers are also interested in the theoretical lessons in their current analysis. It can help us understand what correct ones between quantum states distributed in the room, or smell ae after another in time – are allowed and can be manipulated. Xianjing Liu says work can become part of a new framework for understanding quantum processes, one that separates time and space less than traditional approaches.