Non-cloning theorem, the basis of the infalling note, was first put into practice in France. Process involves changing photons between the user and a quantum bank.
The idea of quantum money has just become more real. A group of researchers has developed a kind of “debit card” capable of storing a currency impossible to falsify.
The concept of quantum money was initially proposed in 1983 by physicist Stephen Wiesner, who used the call Non-Cloning Theorem – A fundamental law of quantum physics that prevents the exact copy of quantum information – as the basis for creating infalling notes.
The proposal, considered the founder of quantum encryption, had never been practically tested that it allowed the storage of the currency – so far, tells.
The team of Julien Lauratfrom the Kastler Brossel laboratory in France, he got it for the first time keep quantum “notes” through an integrated memory device in the system.
The process involves light particle exchangeor photons, between the user and the quantum bank, according to the study on September 19 at Science Advances. The states of these photons can be deposited in memory – functioning how to carry balance on a debit card – and recovered later without loss of quantum information.
To build this memory, scientists resorted to hundreds of millions of cooled cesium atoms to only a few millionths of a degree above the absolute zero, with lasers. Under these extreme conditions, the quantum states of atoms could be manipulated with great accuracy. After years of testing, Laurat and colleagues have shown that photons can be stored and released without corrupting the system, something essential for the feasibility of a quantum “bank account”.
Despite the advance, the current storage time reached only six millionths of a second, a limit that makes the technology impractical for real use for now.
The next purpose of the French team is precisely dramatically prolonging this memory time. If it were a thousand times higher, technology could be applied to metropolitan quantum networks already existing in various cities.
In the future, in addition to enabling totally safe monetary transactions, advanced quantum memories can also play a crucial role in long distance quantum communications and in the interconnection of multiple quantum computers, creating more powerful systems.
