Scientists at the University of Waterloo have discovered a method to copy quantum information. This is a significant development because copying this type of data was previously thought to be impossible. Most modern computers use bits to process data, but quantum computers use qubits. A qubit is the smallest unit of information in a quantum system, and it can be stored in tiny particles like light or atoms. These machines have the potential to solve problems that are too difficult for regular computers, but they face a rule called the no-cloning theorem. This rule states that quantum information cannot be copied directly because the data is very delicate. If a person tries to look at or copy a qubit, the information inside it can change or disappear.
How encryption allows for quantum data backups
Entangled qubits share information in a way that grows as more of them are linked together. While a single qubit holds very little data, many linked qubits can hold a lot of information. This shared data is what makes quantum computing powerful for tasks like medical research or complex math. The researchers found that they could bypass the cloning rule by using encryption.
By encrypting the information first, the researchers can make as many copies as they want. However, there is a specific rule to this process. The key used to unlock the data only works once. Once a person uses the key to read one copy, that key expires and cannot be used again. This means the other copies remain locked and safe unless a new key is provided. This discovery is important because it allows for quantum cloud storage. Just like people use online drives to back up their photos, this new method allows quantum information to be stored safely in multiple places as a backup. This work helps ensure that quantum data remains secure and reliable as technology advances.
This research is published in Physical Review Letters. An arXiv preprint is available.