An international team of researchers has defined what they call the ‘smallest and most accurate thermometer allowed by the laws of physics.’
Capable of detecting the slightest thermal fluctuations in microscopic regions, the hypothetical device, consisting of only a few atoms, was described in the latest issue of the journal Physical Research Letters.
Developed jointly by mathematicians from the UK’s University of Nottingham and Spain’s Universitat Autònoma de Barcelona, the technology could enable many novel applications in bioscience, chemistry and physics. For example, it could be used to measure thermal variations within biological cells, thus improving diagnostics and the treatment of many diseases.
“In this work we provide a full characterisation of those probes that estimate temperature with maximum accuracy and also the margin of error that must accompany any temperature estimate,” said Gerardo Adesso, who led Nottingham’s involvement in the study. “To that end, we combine the tools of thermodynamics and ‘quantum metrology’, which deals with ultra-precise measurements on quantum systems, finding beautiful and insightful connections between the two.”
The academics also illustrate how by sacrificing some accuracy it is possible to gain other desirable features in a thermometer, such as a constant sensitivity over a wide range of temperatures.
Finally, they also looked at the maximum accuracy achievable in realistic situations in which the time available for the temperature measurement may be short due to unavoidable experimental limitations.
The study was funded by the European Research Council, which provides grants for scientific projects that enable Europe’s brightest minds to tackle research challenges such as climate change, health and ageing and economic governance.