The world's first link-layer protocol brings the quantum internet closer to reality

QuTech researchers have achieved a world first in quantum Internet technology. A team led by Professor Stephanie Wehner has developed a so-called link-layer protocol that transforms the phenomenon of quantum entanglement from experimental physics into a quantum real-world network. This brings closer the day when the quantum internet can become a reality by offering applications impossible to achieve via the classic internet. The work was presented today to ACM SIGCOMM.

In classical computing, a set of software layers called a network stack allows computers to communicate with each other. The network stack underlies communication protocols, such as the Internet Protocol or HTTP. Stephanie Wehner explained that one of the essential protocols used by a network is the link-layer protocol, which solves the problems caused by imperfect hardware: "We use all the conventional link-layer protocols in everyday life . An example is Wi-Fi, which allows radio signal – suffering from interrupts and interference – to be used to transmit data reliably between compatible devices. "

A quantum network, based on the transmission of quantum bits, or qubits, requires the same level of reliability. Stephanie Wehner said, "In our work, we proposed a quantum network stack and built the world's first link-layer protocol for a quantum network."

It turns out that existing classical protocols can only help in the quantum world. A challenge is presented by the differences between the technologies used. Stephanie Wehner: "Currently, qubits can not be kept in memory for a very long time, which means that control decisions about what to do with them must be done very quickly." By creating this link layer protocol, we have overcome the obstacles presented by a very demanding physics. "

There are also fundamental differences between a future quantum Internet and the Internet that we see today. Stephanie Wehner said that two quantum bits can be entangled: "Such entanglement is like a connection, which is very different from the situation for conventional link-layer protocols where we usually send only signals. there is no integrated sense of connection at a fundamental level. "

Quantum Internet

The phenomenon of entanglement forms the basis of a quantum Internet. When two fundamental particles are entangled, they are connected one to the other so that nothing else can participate in this connection. Researcher Axel Dahlberg said that this allowed for a whole new range of applications. "Security is an important application.It is physically impossible to listen to a network connection entangled between two users.To give another example, the technology also allows for improved synchronization of the clock.Can attach astronomical telescopes Far apart one from the other, so they act as a huge single telescope.

Researcher Matthew Skrzypczyk said that an important feature of the proposed quantum network stack and link-layer protocol is that any future software written using this protocol will be compatible with many platforms of quantum material. "Someone who uses our link-layer protocol no longer needs to know what is the underlying quantum material." In our article, we study the protocol performance on Nitrogen-Vacancy diamond centers. , which are essentially small quantum computers, but our protocol can also be implemented on Ion Traps, for example It also means that our link layer protocol can be used in the future on many types of quantum hardware. . "

Build a quantum network system

Stephanie Wehner said the next step will be to test and demonstrate a new network layer protocol using the link-layer protocol: "Our link-layer protocol allows us to reliably generate entanglement between two network nodes connected by a direct physical link, such as a telecommunication network The next step is to create entanglement between network nodes that are not directly connected by a fiber, using an intermediate node. quantum networks on a large scale, it is important to go beyond the framework of a physical experiment and build a quantum network system.This is one of the objectives of the Quantum Internet Alliance (QIA), funded by the EU . "