Researchers from the University of Waterloo and Kyushu University have achieved a groundbreaking advancement in quantum computing by developing a novel method to create redundant, encrypted copies of qubits. This represents a pivotal step towards practical quantum cloud services and robust quantum infrastructure.
In quantum mechanics, the no-cloning theorem asserts that creating an identical copy of an unknown quantum state is impossible.
Dr. Achim Kempf from the University of Waterloo and Dr. Koji Yamaguchi from Kyushu University emphasize that this fundamental rule remains intact.
However, they have demonstrated a method to generate multiple encrypted versions of a single qubit.
“This significant breakthrough facilitates quantum cloud storage solutions, such as quantum Dropbox, quantum Google Drive, and quantum STACKIT, enabling the secure storage of identical quantum information across multiple servers as redundant encrypted backups,” said Dr. Kemp.
“This development is a crucial step towards establishing a comprehensive quantum computing infrastructure.”
“Quantum computing offers immense potential, particularly for addressing complex problems, but it also introduces unique challenges.”
“One major difficulty in quantum computing is the no-duplication theorem, which dictates that quantum information cannot be directly copied.”
“This limitation arises from the delicate nature of quantum information storage.”
According to the researchers, quantum information functions analogously to splitting passwords.
“If you possess half of a password while your partner holds the other half, neither can be utilized independently. However, when both sections are combined, a valuable password emerges,” Dr. Kemp remarked.
“In a similar manner, qubits are unique in that they can share information in exponentially growing ways as they interconnect.”
“A single qubit’s information is minimal; however, linking multiple qubits allows them to collectively store substantial amounts of information that only materializes when interconnected.”
“This exceptional capability of sharing information across numerous qubits is known as quantum entanglement.”
“With 100 qubits, information can be simultaneously shared in 2^100 different ways, allowing for a level of shared entangled information far exceeding that of current classical computers.”
“Despite the vast potential of quantum computing, the no-cloning theorem restricts its applications.”
“Unlike classical computing, where duplicating information for sharing and backup is a common practice, quantum computing lacks a simple ‘copy and paste’ mechanism.”
“We have uncovered a workaround for the non-replicability theorem of quantum information,” explained Dr. Yamaguchi.
“Our findings reveal that by encrypting quantum information during duplication, we can create as many copies as desired.”
“This method circumvents the no-clonability theorem because when an encrypted copy is selected and decrypted, the decryption key is automatically rendered unusable; it functions as a one-time key.”
“Nevertheless, even one-time keys facilitate crucial applications such as redundant and encrypted quantum cloud services.”
The team’s research will be published in the journal Physical Review Letters.
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Koji Yamaguchi & Achim Kempf. 2026. Encrypted qubits can be cloned. Physical Review Letters in press. arXiv: 2501.02757
Source: www.sci.news
