Researchers in the Netherlands have shown that they can transmit quantum data through an intermediary node, which is necessary to make the quantum internet possible.
In recent years, scientists have argued that the quantum internet, while necessary for connecting multiple quantum systems, provides a more desirable network for secure data transfer. All of these, among others, attract investment from the US government.
Despite the promises, vital elements are still missing to create a functional quantum internet.
The transfer of quantum information between two network nodes—the superposition of states—occurs when scientists create two or more particles so that the quantum state of each particle cannot be described independently of the states of the others. In this way, the researchers showed that they could “teleport” quantum information between two nodes.
Researchers at Qutech, a quantum computing research institute founded in 2014 by Delft University of Technology and the Netherlands Organization for Applied Scientific Research, have now demonstrated that they can create the effect through an intermediary node, a prerequisite for a functioning computer network.
As a learning tool in an otherwise hard-to-decipher field, PhD student Sophie Hermans and her colleagues named the network nodes with nicknames associated with the infoseccers among us: Alice, Bob, and Charlie. Alice and Charlie are not directly related.
The researchers’ demonstration first creates entangled quantum states between neighboring nodes: Alice and Bob. The second node, or processor, then maintains the tangled state. Then Bob creates a mixed state with Charlie. Quantum scientists then used a peculiar effect known in their field. By measuring Bob’s condition, they affect the entanglement, creating a direct link between Alice and Charlie.
According to a paper published this week in Nature, the team then encoded the “message” information in an additional qubit, which, when measured along with Charlie’s entangled state, transmits information to Alice.
As with much of the field of quantum computing, while there is a significant demonstration of working concepts that can be important in quantum networks, practical applications are some way off.
Oliver Slattery, Ph.D., of the Information Technology Laboratory of the National Institute of Standards and Technology in Maryland, and Yong-Su Kim, senior scientist at the Center for Quantum Information at the Korea Institute of Science and Technology, wrote in an accompanying paper that the information surrounding the quantum network of permanent teleportation remained somewhat distant.
“Hermans et al [have] He managed to teleport quantum information between Alice and Charlie – two nodes that are not directly connected. This achievement is not only a victory for fundamental science, but also represents a breakthrough in solving the real-world problem required to take this exciting quantum application to the next level.
“Reliable teleportation around a quantum network is some way off, and this work highlights a major challenge ahead for the actual implementation of a quantum internet — but Hermans et al. suggest a potential way forward. Increasing the robustness of the memories used to store entanglement is even higher. rates, and an improved optical interface will increase the efficiency with which remote nodes are mixed,” they said.
Three network nodes, Alice (A), Bob (B), and Charlie (C), are connected via fiber optic links (lines) in a line configuration. Each setup has a communication qubit (purple) that allows it to entangle with a neighboring node
Nevertheless, the promise of transporting quantum data securely around the network holds so much power that the US government is determined not to be left out.
In 2020, the US Department of Energy developed a “strategy plan” to develop a national quantum internet.
Energy Secretary Dan Brouillette said, “By building this new and emerging technology, the United States continues its commitment to protect and expand our quantum capabilities.”
A US government statement at the time said that the quantum internet “could become a secure communications network and have a profound impact on areas critical to science, industry and national security”. ®