Nottingham: Scientists have defined the smallest, most
accurate thermometer allowed by the laws of physics — one that could
detect the smallest fluctuations in microscopic regions, such as the
variations within a biological cell. The research, involving mathematicians at
The University of Nottingham and published in the latest edition of the
journal Physical Review Letters,
focuses on the sensitivity of thermometers made up of just a handful of
atoms and small enough to exhibit distinctive ‘quantum’ features.
Devising sensitive and practical
nano-scale thermometers would represent a huge leap forward as such
technology would enable a plethora of applications in bioscience,
chemistry, physics and in the diagnosis and treatment of many diseases.
The study was conducted as part of an
ongoing collaboration between the Quantum Correlations Group in
Nottingham’s School of Mathematical Sciences and the Quantum Information Group at Universitat Autònoma de Barcelona.
Dr Gerardo Adesso, who led Nottingham’s
involvement in the study, said: “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. 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.