Scientists Detect Tiniest Energy Signal Ever Measured

Scientists in Finland just measured one of the smallest energy signals ever detected, and it could help us unlock some of the universe's deepest secrets.

Researchers at Aalto University built an ultra-sensitive sensor that detected an electromagnetic pulse measuring just 0.83 zeptojoules. To put that in perspective, a zeptojoule is less than a trillionth of a billionth of a joule, roughly the energy needed to move a single red blood cell upward by one nanometer.

The team, led by Academy Professor Mikko Möttönen, used a special device called a calorimeter that combines two types of metals: superconductors that carry electricity without resistance, and normal conductors that resist electrical flow. When even the tiniest amount of energy enters this system, it creates a temperature change so small it's almost impossible to imagine, yet the sensor catches it.

"That combination of metals makes superconductivity such a fragile phenomenon that it weakens immediately if the temperature in the ultracold conductor rises even a little bit," Möttönen explains. This fragility is exactly what makes the sensor so powerful.

The breakthrough marks the first time a calorimetric measurement device has reached this level of sensitivity. Published in Nature Electronics, the research opens exciting possibilities for technologies that seemed out of reach just years ago.

Why This Inspires

This discovery could transform quantum computing by providing a gentler way to read information from qubits, the building blocks of quantum computers. Because the calorimeter operates at the same ultra-cold temperatures that qubits need, it won't disturb delicate quantum systems the way current measurement tools do.

Even more thrilling, the technology might help scientists detect dark matter particles called axions that could be traveling through space right now. "We want to make this setup capable of measuring input that has an arbitrary time of arrival, which is important for things like detecting dark-matter axions in space when you have no idea when they might reach your system," the team notes.

The researchers also believe their sensor could eventually count individual photons, particles of light. This capability has been a long-standing goal in quantum technology and astrophysics, potentially revealing new details about how light and energy work at their most fundamental levels.

The work was supported by the Future Makers initiative and carried out at OtaNano, Finland's national research infrastructure for nano and quantum technologies. What started as a physics experiment in ultra-cold conditions could soon help us understand the invisible forces shaping our universe.