What is a quantum internet and how can it be made with a diamond?
Physicists often propose things that are validated experimentally decades later. The Nobel Prize in Physics was awarded this year to Alain Aspect, John F. Clauser and Anton Zeilinger for their experiments analyzing quantum entanglement. This phenomenon is the basis for technology such as a quantum internet, which diamonds can enable.
The work of Innsbruck physicist Simon Baier in collaboration with QuTech (Delft University of Technology and the Dutch research organization TNO) that successfully used a three-node tiny network to transfer quantum information was published earlier this year in Communication Physics by Nature. Quantum information, or quantum bits (qubits), can be transmitted through a network called the quantum internet. This could be incredibly safe (data might be transported in an unhackable way) or incredibly powerful (quantum computers could be linked together to boost computational capacity).
Long range entanglement
Quantum information can be transmitted very effectively using “teleportation” between two entangled particles, because even though they are arbitrarily distant from one another, measurement on one directly impacts the state of the other. Range is crucial for a network. For this, they use atomic-level qubits embedded in a diamond known as the nitrogen vacancy center (NV-center). Information is “teleportated” from “Alice” to “Charlie” via “Bob”. Alice (node 1) and Charlie (node 3) are not physically connected, and therefore need Bob (node 2), which is connected to them. This occurs in 3 stages. First, Alice and Charlie becomes connected through a unique series of measurements creating both entanglements between "Bob" and "Alice," as well as between "Bob" and "Charlie”. Then, a qubit or “message” is created in “Charlie”. For instance. "Charlie" measures his quantum state “teleports” this information from him to "Alice." Finally, being entangled with “Alice”, after the measurement is made, the information is displayed on "Alice’s" page.
Teleportation on demand
To avoid erasing the delicate quantum information, the scientists had to put work into improving quantum state preparation, control, and read out, . We are still far from enabling multiple “teleportation” rounds and build expansive quantum networks. However, the researchers intend to reverse steps one and two, i.e., create the teleportable quantum bit first and then prepare the "teleporter," i.e., combine "Alice" and "Charlie." The quantum data must be temporarily stored for this. If this is successful, it will be possible to do teleportation totally on demand and be another important step towards the quantum internet of the future.
Congratulations to the 2022 Nobel laureates in Physics!
Do you want to learn more about real-world applications of quantum science? Reach out to our technology specialist Fleming Bruckmaier!