Quantum communication technology may one day enable the ultra-secure quantum Internet, but so far it has proven difficult to create linkages in such large networks. .. Breakthroughs in the ability to teleport quantum information can be a promising way.
The reason many are so excited about future quantum communication networks is the fact that it is essentially impossible to eavesdrop on quantum-state encoded messages. This is because reading the quantum state of a particle inevitably changes the particle. that’■ You can easily detect if someone is snooping a communication link.
However, in reality, it is difficult to transport quantum states over a considerable distance.Researchers have succeeded in sending a quantum-bound messagetNumber of photons over hundreds Miles of optical cable, It also uses satellite quantum communication to establish links Longer distance.. However, the inevitable signal loss in either mode of communication means that it is difficult to scale up to the distance required for the true Internet.
One workaround is to take advantage of another quantum phenomenon called teleportation. This is very similar to the concept of science fiction used in programs such as: Star TrekAllows you to instantly send information from one location to another, theoretically at an unlimited distance. And now, Dutch researchers have provided the first practical demonstration of how this works.
The team set up three quantum “nodes” called Alice, Bob, and Charlie. These nodes can store quantum information in qubits. This corresponds to a bit of a computer made from the center of the nitrogen vacancy. These are small defects in diamond that can be used to trap electrons and change their quantum states. Then I used fiber optics to connect Alice to Bob and Bob to Charlie.
The goal of the experiment is Paper Nature, It was to teleport quantum information between Alice and Charlie, who are not directly connected. To do that, they first had Create a teleport link between the two. This depends on the quantum phenomenon of entanglement, where the states of the quantum system are so closely related that when one is measured, the other is automatically changed, no matter how far away it is.
protocol We start by using quantum operations to entangle the electrons in Alice’s node with photons. It then fires an optical fiber at Bob, who entangles it with the electrons in the node. This creates an entanglement between Bob and Alice’s qubit.I also need Bobs But to make a connection with Charlie, he transfers the intertwined state that connects him to Alice to another cubit made from the carbon atoms of his diamond. It basically acts as a quantum memory and saves the entangled state for later use.
This frees his electron and creates the same entanglement with Charlie as before. After Bob entangles with both other nodes, he performs an entanglement swapping operation on the entangled state stored in his electron and memory cubits. This will eventually create an entanglement between Alice and Charlie’s cubit.
now that If two unconnected nodes are linked, they will use this shared entangled state. Transfer information From one to another. To do this, Charlie performs an operation called Blind Spot Monitor (BSM). It makes a joint measurement of both the qubit that holds the information you want to send and the qubit that is intertwined with Alice’s qubit.
This causes the quantum state of the information cuebit to instantly teleport to Alice’s cuebit, but the process essentially encrypts it, and additional steps are required to understand it. Charlie sends the BSM results to Alice over a traditional communication channel. It can be used to decode the message and reveal its quantum state.
These experiments were performed on nodes only about 60 feet apart, but as a rule, teleportation should be possible at any distance. This avoids the problem of transmitting quantum information over the optical channel. However, for this setup to work, the previous system had to be significantly upgraded to improve optical communication reliability and memory qubit fidelity.
and Accompanying perspective Nature, Researchers have pointed out that all these factors need to be further developed to realize the true quantum Internet. Nonetheless, this work is a major milestone and will help us clear the critical hurdles for creating global quantum networks.
Image Credit: Marieke de Lorijn for QuTech