Tiangong space station achieves 10 picokelvin quantum record
Scientists on China's Tiangong space station have cooled atoms to 9.7 picokelvin, a new space-based low enabling longer experiments in quantum physics.
China's Tiangong space station has achieved a record-low temperature of 10 picokelvin, or 10 trillionths of a degree above absolute zero. This quantum experiment surpasses the previous best space-based cooling by a factor of four.
The new benchmark of 9.7 picokelvin, with an uncertainty range from 7.0 to 12.9 picokelvin, was measured from the expansion energy of an atom cloud. It is about four times colder than the previous record of 38 picokelvin, which was set in a ground-based drop-tower experiment in Germany. It also undercuts the 52 picokelvin result from NASA's Cold Atom Lab on the International Space Station. The microgravity environment of space is key, as it prevents gravitational sagging that distorts atom clouds on Earth.
Experimental details and duration
Researchers cooled roughly 20,000 rubidium atoms using a combination of laser-based optical dipole traps and evaporative cooling. This process created a Bose-Einstein condensate, a unique state of matter where atoms behave as a single quantum entity. The cloud of atoms was smaller than a grain of sand.
In the weightlessness of orbit, the condensate remained coherent for seven seconds of free expansion. This duration dramatically outlasts previous microgravity attempts. The German drop-tower experiment held a cloud together for two seconds, while the International Space Station experiment managed about one second. The extended coherence time is a direct result of the record-low temperature and stable microgravity.
The team behind the work includes scientists from Peking University and the Chinese Academy of Sciences, with Wei Xiong listed among the authors of the Science paper.
Broader implications for quantum science
This ultra-cold environment opens new pathways for fundamental physics. The primary scientific goal is to study exotic states of matter and test foundational concepts like the equivalence principle. The achievement enables prospects for quantum simulation of exotic quantum phases. It also supports the development of future, highly sensitive space-based atom interferometers.
Krystal Kasal outlined the aim of such research, stating: "First, it aims to enable quantum simulation for exploring low-temperature physics in the unique environment of space."
Expert commentary
Independent physicists have welcomed the results. Nick Bigelow, a physicist at the University of Rochester, described the findings as wonderful results. He noted that his own team has achieved temperatures of about 15 trillionths of a degree in unpublished laboratory work, a figure that shows the extraordinary nature of the space station's 10 picokelvin milestone.
The success paves the way for future quantum experiments in orbit. Scientists aim to extend coherence times even further and probe physics at temperatures colder than ever before.
