Physicists create world's smallest engine

Physicists create world's smallest engine
The world's smallest engine works due to its intrinsic spin, which converts heat absorbed from laser beams into oscillations, or vibrations, of the trapped ion. Credit: Professor Goold, Trinity College Dublin.

Theoretical physicists at Trinity College Dublin are among an international collaboration that has built the world's smallest engine—which, as a single calcium ion, is approximately ten billion times smaller than a car engine.

Work performed by Professor John Goold's QuSys group in Trinity's School of Physics describes the science behind this tiny motor. The research, published today in international journal Physical Review Letters, explains how random fluctuations affect the operation of microscopic machines. In the future, such devices could be incorporated into other technologies in order to recycle and thus improve .

The engine itself—a single calcium ion—is electrically charged, which makes it easy to trap using electric fields. The working substance of the engine is the ion's "intrinsic spin" (its 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 .

"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 Dr. Mark Mitchison of the QuSys group at Trinity, and one of the article's co-authors.

Starting the flywheel from rest—or, more precisely, from its "" (the lowest energy in )—the team observed the little engine forcing the flywheel to run faster and faster. Crucially, the state of the ion was accessible in the experiment, allowing the physicists to precisely assess the energy deposition process.

Assistant Professor in Physics at Trinity, John Goold said: "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 group's research. 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 groundbreaking experiment was carried out by a research group led by Professor Ferdinand Schmidt-Kaler and Dr Ulrich Poschinger of Johannes Gutenberg University in Mainz, Germany.


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More information: Spin Heat Engine Coupled to a Harmonic-Oscillator Flywheel, Physical Review Letters (2019). journals.aps.org/prl/abstract/ … ysRevLett.123.080602
Journal information: Physical Review Letters

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Aug 21, 2019
You'd think they would have used something better than the cosmic space potato to take the picture so we could see the thing more clearly.

Aug 21, 2019
Is it an engine or a motor?

Aug 21, 2019
The terms appear to be synonymous in physics: https://en.wikipe...ki/Motor

An engine or motor is a machine designed to convert one form of energy into mechanical energy.

Aug 21, 2019
A single ion is only ten billion times smaller than a car engine? Ok, that's a reasonable estimate if you only take into account linear dimension, comparing the diameter of a calcium ion to the diameter of a (hypothetically spherical) car engine. A comparison by mass, or by atom count, would push the ratio to about 10^21.

Aug 22, 2019
The engine itself
a single calcium ion
is electrically charged
makes it easy to trap using electric fields
this spin being used to convert heat into oscillations

Because it is so small
Close pack the quantum engines will produce more energy per volume than petrol engines

Aug 22, 2019
Flywheel Vibrations Capturing Energy

Starting the flywheel from rest, from its ground-state: lowest energy
Down the rabbit hole into ground-state

Ground-state of a quantum-mechanical system: its lowest-energy state
Energy of the ground state: zero-point energy of the system
Excited state is any state with energy greater than the ground state

Degenerate energy levels
If it corresponds to two or more different measurable states of a quantum system
Conversely
Two or more different states of a quantum mechanical system are said to be degenerate
giving the same value of energy upon measurement

Zero-point energy
The lowest energy of a quantum mechanical system
Quantum systems constantly fluctuate in their lowest energy state

Degenerate hath two contradictory meaning of states upon measurement
Whereas
Zero-point energy contradicts with Degenerate energy levels

According to Heisenberg's uncertainty principal
What are different states of a quantum mechanical system upon measurement?

Aug 22, 2019
Heisenberg's uncertainty principal upon measurement
Is
Fraught with inconsistencies
Simply
Being that it is Heisenberg's uncertainty principal
These different states of a quantum mechanical system
Upon measurement
Cannot be measured
Under Heisenberg's uncertainty principal
With any degree of certainty

Because of Zero-point energy
The lowest energy of a quantum mechanical system
Quantum systems constantly fluctuate in their lowest energy state

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