Researchers from the University of Science and Technology of China recently succeeded in entangling two clouds of atoms through a 50-kilometer (31-mile) optical fiber. The breakthrough brings us one step closer to a “quantum Internet.”
The experiment brings a quantum Internet one step closer
When two particles are said to be in quantum entanglement, it means that a minute change in one particle’s quantum state will affect the other particle’s state instantly, no matter how far apart they are. For instance, atoms can spin in both directions at once — clockwise and counterclockwise.
This two-way state gets broken when the atoms are measured. “Two atoms can be entangled so that each is in an uncertain two-way state, but their spins are definitely correlated, say, in opposite directions. So if physicists measure the first atom and find it spinning clockwise, they know instantly the other one must be spinning counterclockwise, no matter how far away it is,” according to Science Mag.
A quantum Internet is based on this phenomenon. It would allow communication to be almost unhackable. If a third party were to access the communication, it would mess up the entanglement and alert the two sides that someone was snooping in. If the Chinese were to develop and implement the tech first, this would be a massive hit to the West since China could deploy communication networks that would be immune from spying.
In the study, lead researcher Pan Jianwei and his team sent a powerful laser beam into a cluster of rubidium atoms at one end of the experiment. Some of the metallic atoms ended up being entangled with particles of light called photons. These photons bounced off the atoms and kept moving through the optical fiber, eventually reaching atoms at the other end. It was then that the atoms at both ends became entangled. The team successfully achieved quantum entanglement on particles that were 50 km (31 miles) apart.
Usually, if someone were to send 100 quadrillion entangled photons via optical fiber, just one would survive after the 50-kilometer journey. But Pan’s team succeeded in boosting the survival rate of entangled photons to 1 in 100. The team achieved this breakthrough using a crystal made from lithium, niobium, and oxygen. This crystal can convert entangled light particles into a frequency that is often used for commercial communication.
The researchers believe they might even be able to build a quantum Internet spread over a city once the number of atomic repeaters is increased. In addition to securing communications, a quantum Internet will allow the military to improve the accuracy of its GPS by a great margin, and missiles will have better precision.
Trump’s policy
Last year, the U.S. Army conducted an entanglement experiment using calcium atoms. However, the test only achieved 1 percent transmission efficiency compared to the results reported by Chinese scientists in similar experiments. Realizing the significance of a quantum Internet, the Trump administration’s 2021 budget request has asked for a 20 percent increase in spending on quantum information science to US$237 million. The government wants to allocate US$25 million to develop a national quantum network.
The administration has proposed cutting overall funding for scientific research by 10 percent. This will ensure that the government can reallocate that money to fund the 20 percent increase in quantum research. In 2018, the U.S. set aside US$1.2 billion for quantum research, of which almost US$625 million belongs to the Energy Department, which was recently distributed to various governmental, academic, and industrial research labs.
