Quantum mechanics is a branch of physics that studies the properties and interactions of particles at very small scales, such as atoms and molecules. This has resulted in the development of new technologies that are more powerful and efficient than their conventional counterparts, resulting in breakthroughs in areas such as computing, communication, and energy.
Researchers at the Okinawa Institute of Science and Technology (OIST) have collaborated with scientists from the University of Kaiserslautern-Landau and the University of Stuttgart to design and build an engine based on the special rules that particles obey at very small scales.
They have developed an engine that uses the principles of quantum mechanics to create power, instead of the usual way of burning fuel. The paper describing these results is co-authored by OIST researchers Keerthy Menon, Dr. Eloisa Cuestas, Dr. Thomas Fogarty, and Prof. Thomas Busch and has been published in the journal Nature.
You can combine two fermions into a molecule to convert them to bosons. This new molecule is known as a boson. We can retrieve the fermions by breaking it up. We can power the engine without using heat if we do this cyclically.
Prof. Thomas Busch
In a traditional car engine, a mixture of fuel and air is usually ignited inside a chamber. The resulting explosion heats the gas in the chamber, pushing a piston in and out, producing work that turns the car’s wheels.
The scientists have replaced the use of heat in their quantum engine with a change in the quantum nature of the particles in the gas. To understand how this change can power the engine, we must first understand that all particles in nature can be classified as bosons or fermions based on their unique quantum properties.
At very low temperatures, where quantum effects become important, bosons have a lower energy state than fermions, and this energy difference can be used to power an engine. Instead of heating and cooling a gas cyclically like a classical engine does, the quantum engine works by changing bosons into fermions and back again.
“You can combine two fermions into a molecule to convert them to bosons.” This new molecule is known as a boson. We can retrieve the fermions by breaking it up. We can power the engine without using heat if we do this cyclically,” explained Prof. Thomas Busch, leader of the Quantum Systems Unit.
While this type of engine only works in the quantum regime, the team discovered that its efficiency is quite high, reaching up to 25% with the current experimental setup built by the German collaborators.
This new engine is an exciting development in the field of quantum mechanics and has the potential to lead to further advances in the burgeoning area of quantum technologies. But does this mean we will soon see quantum mechanics powering the engines of our cars? “While these systems can be highly efficient, we have only done a proof-of-concept together with our experimental collaborators,” explained Keerthy Menon. “There are still many challenges in building a useful quantum engine.”
If the temperature rises too high, heat can destroy the quantum effects, so researchers must keep their system as cold as possible. However, running the experiment at these low temperatures requires a significant amount of energy in order to protect the sensitive quantum state.
The research will continue by addressing fundamental theoretical questions about the system’s operation, optimizing its performance, and investigating its potential applicability to other commonly used devices such as batteries and sensors.
