Researchers in Finland have achieved a significant advance in ultra-sensitive measurement technology, detecting an amount of energy smaller than one zeptojoule. This breakthrough, detailed in the journalNature Electronics, could enhance quantum computing, aid the search for dark matter, and eventually enable the counting of individual photons.
A zeptojoule represents an almost impossibly small quantity of energy, roughly equivalent to the work needed to lift a red blood cell by one nanometer against Earth's gravity. The research team, led by Academy Professor Mikko Möttönen at Aalto University, collaborated with quantum computing company IQM and the Technical Research Centre of Finland (VTT).
Quantum Sensor Breakthrough
To reach this level of sensitivity, the researchers employed a calorimeter, a device designed to measure minute changes in heat energy. Measuring such tiny signals presents a far greater challenge than simply directing a beam into a detector.
Scientists directed a microwave pulse into a sensor constructed from two types of metals. One section utilized superconductors, which allow electricity to flow without resistance. The other section incorporated normal conductors, which resist electrical flow. "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. This makes it such a sensitive setup," Möttönen explained. He is also a founder of quantum computer firm IQM.
Implications for Dark Matter and Qubits
To reach this level of sensitivity, the researchers employed a calorimeter, a device designed to measure minute changes in heat energy.
After filtering the signal, the researchers confirmed the detection of an electromagnetic pulse measuring 0.83 zeptojoules. This marks the first instance a calorimetric measurement device has achieved such sensitivity, according to the team.
The advance could allow scientists to count individual photons, a long-standing objective in quantum technology and astrophysics.
Möttönen noted, "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 technology may also prove useful in quantum computers, as the calorimeter operates at the same millikelvin temperatures required by qubits, the fundamental units of quantum information. The work used facilities at OtaNano, Finland's national research infrastructure for nano-, micro-, and quantum technologies.
COMMENTS