New Quantum Verification Method Boosts Tech Development

Researchers at the University of Vienna develop an efficient real-time technique to certify entangled quantum states without destroying them.

Published on Feb. 14, 2026

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Entangled quantum states are the building blocks of emerging quantum technologies, but verifying their quality has been a resource-intensive process that destroys the states in the measurement. Researchers at the University of Vienna have developed a new protocol using optical switches to randomly sample and certify quantum states in real-time without destroying the unmeasured states, a crucial step forward for practical quantum computing and communication networks.

Why it matters

Verifying the integrity of delicate quantum states is essential before they can be used in real-world quantum applications like secure communication and powerful computing. The new method from the University of Vienna overcomes the limitations of existing verification techniques, which require destroying all available quantum states during the testing process. This breakthrough enables more efficient and scalable certification of quantum systems, paving the way for more reliable and practical quantum technologies.

The details

The researchers' new protocol uses active optical switches to randomly forward individual quantum states either to a verifier for certification or to a user for the actual quantum task. This allows the verifier to statistically certify the quality of the unmeasured states in real-time without destroying them. The method also overcomes the previous assumption that all generated quantum states must be identical, making it more robust for real-world use. Additionally, the new protocol enables device-independent certification, ensuring the validity of the process even if the measuring devices are not fully trustworthy.

  • The research was carried out in Philip Walther's laboratories at the University of Vienna and published in the journal Science Advances in February 2026.

The players

University of Vienna

A public research university in Vienna, Austria that has been a center of academic excellence for over 650 years, ranked among the top 100 universities worldwide.

Philip Walther

A professor at the University of Vienna and the lead author of the study published in Science Advances.

Lee Rozema

A researcher at the University of Vienna and one of the lead authors of the study.

Michael Antesberger

A researcher at the University of Vienna and co-first author of the study.

Mariana Schmid

A researcher at the University of Vienna and co-first author of the study.

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What they’re saying

“The key to the practical implementation of this protocol is the use of active optical switches. These switches allow us to randomly forward individual quantum states either to a verifier (for certification) or to a user (for the actual quantum task).”

— Lee Rozema, Researcher, University of Vienna (Mirage News)

“Our experimental setup successfully implements this advanced certification protocol in real time, which is a crucial step towards practical, secure quantum technologies.”

— Michael Antesberger, Researcher, University of Vienna (Mirage News)

“This method is incredibly efficient, offers optimal scalability and significantly reduces the resource requirements for robust certification.”

— Mariana Schmid, Researcher, University of Vienna (Mirage News)

“This work paves the way for more reliable quantum communication networks and advanced photonic quantum computers. This will be crucial for benchmarking the large-scale quantum networks of tomorrow.”

— Philip Walther, Professor, University of Vienna (Mirage News)

What’s next

The researchers plan to further develop and scale up their real-time quantum state verification protocol to enable more robust and practical quantum technologies.

The takeaway

This breakthrough from the University of Vienna represents a major advancement in the field of quantum verification, overcoming key limitations of existing methods and paving the way for more reliable and efficient quantum computing and communication systems that can be thoroughly tested without destroying the underlying quantum states.