Scientists think it will be particularly useful for problems involving many variables, such as analyzing financial risk, encrypting data and studying the properties of materials.
Researchers doubt people will own personal quantum computers in the foreseeable future. Instead, they will be hosted at academic institutions and private companies where they can be accessed via a cloud service.
How does the quantum internet work?
Quantum computers use fundamental units of information similar to the bits used in classical computing. These are called qubits.
However, unlike conventional computer bits, which transmit information such as 0 or 1 qubits, they transmit information through a combination of quantum states, which are unique conditions found only on the subatomic scale.
For example, one quantum state that could be used to encode information is a property called spin, which is the intrinsic angular momentum of an electron. Spin can be thought of as a tiny compass needle pointing up or down. Researchers can manipulate that needle to encode information in the electrons themselves, just as they would with conventional bits, but in this case, the information is encoded in a combination of possible states. Qubits are neither 0 nor 1, but rather both and neither, in a quantum phenomenon called superposition.
This allows quantum computers to process information in a completely different way than their conventional counterparts, and thus can solve some types of problems that would take even the largest supercomputers decades to complete. These are problems like factoring large numbers or solving complex logistical calculations (see the traveling salesman problem). Quantum computers would be particularly useful for encryption and for discovering new types of drugs or new materials for solar cells, batteries or other technologies.
But to unlock that potential, a quantum computer must be able to process a large number of qubits, more than any single machine can currently handle. That is, unless several quantum computers can be brought together through the quantum internet and their computational power pooled, creating a much more capable system.
There are several types of qubits under development, and each has distinct advantages and disadvantages. The most common qubits studied today are quantum dots, ion traps, superconducting circuits, and faulty spin qubits.
What can the quantum internet do?
Like many scientific advances, we won’t understand everything the quantum internet can do until it’s fully developed.
Few could have imagined 60 years ago that one day a handful of interconnected computers would generate the vast digital landscape we know today. The quantum internet has a similar unknown, but numerous applications have been theorized and some have already been demonstrated.
Thanks to the unique quantum properties of qubits, scientists think the quantum internet will greatly improve information security, making it nearly impossible to intercept and decrypt quantum encrypted messages. Quantum key distribution, or QKD, is a process by which two parties share a cryptographic key over a quantum network that cannot be tapped. Several private companies already offer the 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 information, is nearly impossible for modern computers to break; however, quantum computers with enough processing power could 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 has focused on black hole gravitational waves, microscopy and electromagnetic imaging.
The creation of a purely quantum Internet would also alleviate the need for quantum information to move from classical to quantum systems, which is a major obstacle in current systems. Instead, it would allow a collection of individual quantum computers to process information as one conglomerate machine, giving them far greater computing power than any single system could command alone.
“The quantum internet represents a paradigm shift in how we think about secure global communication,” said David Awschalom, Liew Family Professor in Molecular Engineering and Physics at the University of Chicago, director of the Chicago Quantum Exchange and director of Q -NEXT , a Department of Energy quantum information science center in Argonne. “Being able to create an intricate network of quantum computers would allow us to send unhackable encrypted messages, keep technology in perfect sync over long distances using quantum clocks, and solve complex problems that a quantum computer could struggle with on its own, and those are just a few of the applications we know of right now. The future is likely to hold amazing and impactful breakthroughs using quantum networks.”
How far away is the quantum internet?
To date, no one has been able to successfully create a large-scale sustained quantum network, but there has been great progress.
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 be part of a quantum network, but the system was only able to recover one photon for every 6 million, too few to be used for reliable communications.
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