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QUTE.sk research confirms 83.3% cloning limit after 30 years of quantum study

Ivy Delaney
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⚡ Quantum Brief
Researchers at QUTE.sk have experimentally confirmed the 83.3% fidelity limit for cloning unknown quantum states, a theoretical boundary first proposed by Vladimír Bužek and Mark Hillery in 1996. Their Bužek-Hillery quantum cloning machine established that perfect copying is impossible under quantum mechanics, but near-perfect replication is achievable, with 16.7% of information inevitably lost. The Slovak National Center for Quantum Technologies validated this 30-year-old prediction, demonstrating its universality across all quantum states. The work reinforces the no-cloning theorem’s role in quantum cryptography, where any eavesdropping attempt would disturb the state, alerting legitimate users.
Why it matters

This confirmation cements a foundational constraint in quantum information, validating the theoretical ceiling for quantum copying and reinforcing the security of quantum communication protocols that rely on the no-cloning principle.

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Quantum News · Media Library

Thirty years after establishing a fundamental limit in quantum copying, research from QUTE.sk confirms that 83.3 percent is the maximum fidelity achievable when cloning an unknown quantum state. In 1996, Vladimír Bužek and Mark Hillery published their findings in Physical Review A, introducing the Bužek-Hillery quantum cloning machine and defining a universal constraint applicable to all quantum states, the company says. “The optimal quantum cloner provides a precise way of understanding the boundary between what quantum mechanics forbids and what it permits,” the researchers wrote, revealing that perfect copying remains impossible, yet near-perfect replication is attainable. This result underpins the security of quantum cryptography and continues to shape modern quantum information science. This means that even with optimal technology, approximately 16.7 percent of the original quantum information is inevitably lost during the copying process, a fundamental constraint dictated by the laws of quantum mechanics. This confirmation arrives as the Slovak National Center for Quantum Technologies marks 30 years since the publication of the foundational work by Vladimír Bužek and Mark Hillery. In 1996, Bužek and Hillery published “Quantum copying: Beyond the no-cloning theorem” in Physical Review A, introducing a model that predicted the 5/6 fidelity limit for quantum state replication. This wasn’t merely a theoretical exercise; the researchers demonstrated that imperfect copying is possible, despite the well-known no-cloning theorem which prohibits the creation of identical quantum copies. The universality of this limit is particularly noteworthy, applying equally to all attempted quantum states, regardless of their complexity or characteristics. The implications of this work extend far beyond theoretical curiosity, becoming deeply interwoven with the development of quantum cryptography. The no-cloning principle, as demonstrated by the Bužek-Hillery machine, underpins the security of these systems; any attempt by an eavesdropper to intercept and copy a quantum key would inevitably disturb the state, alerting the legitimate parties, according to the company. The paper has garnered over a thousand citations, solidifying its place as a cornerstone of Slovak quantum physics and influencing subsequent research, including the 2005 Reviews of Modern Physics article on quantum cloning by Scarani, Iblisdir, Gisin and Acín. QUTE.sk emphasizes that expertise in quantum technologies is not built quickly, but through decades of dedicated work and contributions that endure, pointing to the lasting relevance of the Bužek-Hillery result as an example of work that “cannot be cloned” and has stood the test of time. The continued validation of this 30-year-old prediction reinforces its importance as a fundamental principle guiding the development of future quantum technologies and ensuring the security of quantum communication networks. Source: https://www.qute.sk/30-years-of-slovak-quantum-research-the-legacy-of-the-buzek-hillery-cloning-machine/ More like thisQuantum AlgorithmsQuantum Agency: No-Cloning Limits World-Model CreationQuantum PhysicsRadboud & TU Darmstadt Prove Quantum Copying Limits in C*-AlgebrasQuantum MechanicsClassical Data Defines Limits to Copying and ChangeQuantum ComputingQuantum Measurements Show Non-Classical FeaturesStay currentSee today’s quantum computing news on Quantum Zeitgeist for the latest breakthroughs in qubits, hardware, algorithms, and industry deals. Tags: Ivy Delaney Ivy Delaney has been working with neural networks and machine learning since the mid-nineties, back when a couple of hidden layers and a long afternoon of training counted as ambitious. She has watched the field go from academic curiosity to the thing quietly running underneath everything, and she brings that long view to quantum computing.

For Quantum Zeitgeist she covers the ground where the two fields meet. That means quantum machine learning and the variational algorithms it leans on, and it also means the less glamorous but more interesting story of classical machine learning already doing real work inside quantum machines, decoding error-correcting codes, calibrating noisy hardware and learning the error models that simulators depend on. She writes about the hardware those algorithms have to run on too, and about the post-quantum cryptography scramble that the same hardware has set off. Her stories typically start with the paper, whether that is peer-reviewed work, conference proceedings or an arXiv preprint, with the source linked so you can hold a claim up against the research it came from. She is unimpressed by benchmarks that will not say what they beat, and by demonstrations that only work in the press release. Latest Posts by Ivy Delaney: Quantum QC Ware and IonQ reach 4% accuracy in drug-design workflow September 1, 2026 Superconducting qubits reset and read in under a resonator cycle September 1, 2026 Quantum scientists map exciton wave functions in organic films September 1, 2026

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