A team of researchers from Trinity College Dublin and the Universität Mainz has developed the world’s smallest engine.
The nanoscale heat engine. Image credit: John Goold, Trinity College Dublin.
The nanoscale engine — a trapped 40Ca+ ion — is approximately 10 billion times smaller than a car engine.
It is electrically charged, which makes it easy to trap using electric fields.
The working substance of the engine is the ion’s ‘intrinsic spin’ (angular momentum). This spin is used to convert heat absorbed from laser beams into oscillations, or vibrations, of the trapped ion.
These vibrations act like a ‘flywheel,’ which captures the useful energy generated by the engine. This energy is stored in discrete units called ‘quanta,’ as predicted by quantum mechanics.
“The flywheel allows us to actually measure the power output of an atomic-scale motor, resolving single quanta of energy, for the first time,” said team member Dr. Mark Mitchison, a scientist at Trinity College Dublin.
The world’s smallest engine works due to its intrinsic spin, which converts heat absorbed from laser beams into oscillations of the trapped ion. Image credit: John Goold, Trinity College Dublin.
Starting the flywheel from rest — or, more precisely, from its ‘ground state’ — the team observed the little engine forcing the flywheel to run faster and faster.
Crucially, the state of the 40Ca+ ion was accessible in the experiment, allowing the researchers to precisely assess the energy deposition process.
“This experiment and theory ushers in a new era for the investigation of the energetics of technologies based on quantum theory, which is a topic at the core of our research,” said Dr. John Goold, also from Trinity College Dublin.
“Heat management at the nanoscale is one of the fundamental bottlenecks for faster and more efficient computing.”
“Understanding how thermodynamics can be applied in such microscopic settings is of paramount importance for future technologies.”
The team’s work was published in today’s issue of the journal Physical Review Letters.
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D. von Lindenfels et al. 2019. Spin Heat Engine Coupled to a Harmonic-Oscillator Flywheel. Phys. Rev. Lett 123 (8): 080602; doi: 10.1103/PhysRevLett.123.080602
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