Scientists believe it will be particularly useful for problems involving many variables, such as financial risk analysis, data encryption and studying the properties of materials.
Researchers doubt that individuals will own personal quantum computers in the near future. Instead, they will be hosted at academic institutions and private companies, accessible through cloud services.
How does the quantum internet work?
Quantum computers use basic units of information similar to bits used in classical computing. These are called “qubits”.
However, unlike conventional computer bits, which transmit information as 0s or 1s, qubits transmit information only through combinations of quantum states, which are unique conditions found at the subatomic scale.
For example, one quantum state that can be used to encode information is a property called spin, which is the intrinsic angular momentum of an electron. Rotation can be thought of as a small compass needle pointing up or down. Researchers can manipulate this needle to encode information into the electrons themselves, as with ordinary bits—but in this case, the information is encoded in combinations of possible states. In a quantum phenomenon called superposition, qubits are not 0 or 1, but rather both and neither.
This allows quantum computers to process information in a completely different way than their conventional counterparts, and so they can solve certain problems that would take even the largest supercomputers decades to complete. These are problems such as factoring a large number or solving complex logistic calculations (see the traveling salesman problem). Quantum computers would be particularly useful for cryptography, as well as for the discovery of new types of pharmaceutical drugs or new materials for solar cells, batteries or other technologies.
But to unlock this potential, a quantum computer would need to be able to process large numbers of qubits—more than any machine can currently handle. That is, unless several quantum computers can be connected via a quantum internet and their computing power combined to create a more capable system.
There are several different types of qubits in development, and each has distinct advantages and disadvantages. The most common qubits studied today are quantum dots, ion traps, superconducting circuits, and defect spin qubits.
What can the quantum internet do?
Like many scientific advances, we won’t fully understand all that the quantum internet can do until we fully develop it.
60 years ago, few could have imagined that interconnected computers could one day create the vast digital landscape we know today. The quantum internet presents a similar unknown, but a number of applications have been theorized and some have already been demonstrated.
Thanks to the unique quantum properties of qubits, scientists believe that the quantum internet will significantly improve information security and make it nearly impossible to intercept and decipher quantum-encrypted messages. Quantum key distribution, or QKD, is a process where two parties share a cryptographic key over an impenetrable quantum network. Several private companies already offer this process, and it has even been used to secure national elections.
At the same time, quantum computers pose a threat to traditional encrypted communications. RSA, the current standard for protecting sensitive digital data, makes modern computers nearly impossible to crack; however, quantum computers with sufficient processing power can crack RSA encryption in minutes or seconds.
A fully realized quantum network could significantly improve the accuracy of scientific instruments used to study certain phenomena. The impact of such a network would be far-reaching, but initial interest focused on gravitational waves from black holes, microscopy, and electromagnetic imaging.
Creating a purely quantum internet would also eliminate the need for quantum information to switch between classical and quantum systems, which is a significant bottleneck in existing systems. Instead, it would allow a number of individual quantum computers to process data as a conglomerate machine, giving them more computing power than any single system could command on its own.
“The quantum internet represents a paradigm shift in how we think about secure global communications,” said David Awschalom, Liew Family Professor of Molecular Engineering and Physics at the University of Chicago, director of the Chicago Quantum Exchange and director of Q-NEXT. , Argonda Energy Quantum Information Science Center Department. “Being able to create an entangled network of quantum computers would allow us to send unbreakable encrypted messages, use quantum clocks to keep technology perfectly synchronized over long distances, and solve complex problems that a single quantum computer would struggle with on its own. Some of the applications we know about now. Using quantum networks in the future will make surprising and impressive discoveries.”
How far is the quantum internet?
To date, no one has successfully created a large-scale continuous quantum network, but great progress has been made.
In 2017, researchers at the University of Science and Technology of China used lasers to successfully transmit entangled photons between an orbiting satellite and ground stations more than 700 miles below. The experiment showed the possibility of using satellites to form part of a quantum network, but the system was able to recover only one photon in 6 million – too few to use for reliable communication.