Quantum Clocks Consume More Energy When Observed, Study Finds

Oxford research reveals the thermodynamic cost of measuring quantum time is far higher than running the clock itself.

Jan. 31, 2026 at 6:31pm

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New research from the University of Oxford shows that reading a quantum clock uses vastly more energy than running the clock itself. The findings could reshape how future quantum technologies are built and understood, as quantum computers, sensors, and communication systems all rely on precise timing. The study also contributes to the understanding of fundamental physics, reinforcing the connection between energy, entropy, and information at the quantum level.

Why it matters

For technologies that depend on highly precise clocks, like quantum computers or navigation systems, understanding the energy needed to keep and read time is crucial. Until now, the thermodynamics of quantum clocks remained largely a mystery. This study provides important insights that will help engineers design quantum devices more efficiently, while also deepening our understanding of time, entropy, and energy in nature.

The details

Researchers at Oxford built a microscopic clock using a double quantum dot, two tiny regions that can trap individual electrons. They tracked the electron jumps between the regions, which act as 'ticks' of the clock, using two methods: measuring electrical currents and tracking changes with radio waves. The team's calculations revealed that the entropy generated by measurement and amplification was up to a billion times larger than the energy needed to move the electrons, meaning reading the clock costs far more than running it.

  • The study was published on February 1, 2026.

The players

Natalia Ares

Lead author of the study and Professor at Oxford's Department of Engineering Science.

Vivek Wadhia

PhD student at Oxford and co-author of the study.

Florian Meier

PhD student at Technische Universität Wien who provided additional context on the findings.

University of Oxford

The institution where the research was conducted.

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What they’re saying

“Quantum clocks running at the smallest scales were expected to lower the energy cost of timekeeping, but our new experiment reveals a surprising twist. Instead, in quantum clocks, the quantum ticks far exceed that of the clockwork itself.”

— Natalia Ares, Professor, Oxford Department of Engineering Science (The Brighter Side of News)

“Our results suggest that the entropy produced by the amplification and measurement of a clock's ticks, which has often been ignored, is the most important thermodynamic cost of timekeeping at the quantum scale.”

— Vivek Wadhia, PhD Student, Oxford (The Brighter Side of News)

“By showing that it is the act of measuring — not just the ticking itself — that gives time its forward direction, these findings link the physics of energy to the science of information. Essentially, the very act of observation makes the passage of time irreversible.”

— Florian Meier, PhD Student, Technische Universität Wien (The Brighter Side of News)

What’s next

The research provides a roadmap for future studies in quantum timekeeping and nanoscale devices. Engineers designing autonomous systems or quantum computers can use these insights to reduce energy loss while maximizing accuracy. Scientists can also explore other ways to read quantum information more efficiently, possibly revolutionizing the way we think about measurement, clocks, and energy at the smallest scales.

The takeaway

This study overturns assumptions in quantum thermodynamics by proving that the energy cost of measurement cannot be ignored when it comes to quantum clocks. It highlights a trade-off between measurement precision and energy efficiency, which will be crucial for the design of future quantum technologies. Beyond practical applications, the findings also contribute to our fundamental understanding of time, entropy, and energy at the quantum level.