Advancements at Harvard University and the University of Science and Technology of China are paving the way towards the establishment of a quantum internet, an innovative network that would offer secure, unbreakable links and connect quantum computers leveraging the entanglement principle.
These strides address a pivotal obstacle in long-distance transmission of entangled quantum bits (qubits) – devising a quantum repeater.
Innovation in Entanglement Storage
Essential to a quantum internet are entangled qubits, which enable instantaneous influence regardless of distance, contrasting with current data transfer that uses digital bits conveyed by electrical or optical signals. However, qubits have the potential to transform how we transmit data thanks to their distinctive attributes. “For quantum communication across vast distances, a quantum repeater—which has not been realized yet—is indispensable as it would capture and replicate entangled states to bridge longer spans,” explains Alex Wilkins from New Scientist.
The team from Harvard, guided by Can Knaut, constructed a 35-kilometer quantum network loop around Boston, with stations that incorporated communication and memory qubits. Remarkably, their memory qubits maintain quantum states for a duration of up to one second. Knaut states optimistically, “Our experimental work positions us at the brink of demonstrating a quantum repeater,” indicating that a prototype may emerge within the next few years.
Simultaneously, the team led by Xiao-Hui Bao in China successfully interconnected three quantum stations spaced by 10 kilometers each in Hefei. These stations employed frigid clouds of rubidium atoms as memory and intertwined them by means of photon exchange. They homed in on synchronizing photon frequencies, a vital consideration for prospective quantum repeaters, despite their shorter retention of 100 microseconds.
Industry experts acknowledge that these achievements signify a massive step from where quantum internet technology stood a decade ago. “The entanglement rates we see currently are quite slow, obstructed by several system efficiencies,” states Alex Clark from the University of Bristol, UK. Meanwhile, Mohsen Razavi from the University of Leeds affirms the possibility of expanding quantum networks.
The path to a fully operational quantum internet with effective quantum repeaters is dependent on improved rates of entanglement creation and advancements in both quantum and conventional network engineering. Nevertheless, these recent advancements constitute a critical stride towards the quantum internet of the future.
