Scientists reveal exciting possibilities for developing efficient quantum devices. Quantum mechanics is a branch of physics that explores the properties and interactions of particles at extremely small scales, such as atoms and molecules. This has led to the development of new technologies that are more powerful and efficient than traditional technologies, leading to breakthroughs in areas such as computing, communications and energy.
A quantum leap in engine design
At the Okinawa Institute of Science and Technology (OIST), researchers from the Quantum Systems Department, in collaboration with scientists from the University of Kaiserslautern-Landau and the University of Stuttgart, designed and built an engine based on the special rules that particles obey at extremely small scales.
They have developed an engine that uses the principles of quantum mechanics to generate power, rather than the usual way of burning fuel. The paper describing these results was co-authored by OIST researchers Keerthy Menon, Dr. Eloisa Cuestas, Dr. Thomas Fogarty and Professor Thomas Busch, and was published in the journal Nature.
Comparing Classical Engines and Quantum Engines
In a typical classic car engine, a mixture of fuel and air is ignited in a cavity. The heat generated by the explosion heats the gas in the cavity, which in turn pushes the piston in and out, producing work to turn the wheel.
In their quantum engine, the researchers replaced the use of heat by changing the quantum properties of particles in the gas. To understand how this change powers an engine, we need to know that all particles in nature can be classified as either bosons or fermions based on their special quantum properties.
At extremely low temperatures, where quantum effects become important, bosons have a lower energy state than fermions, and this energy difference can be used to power engines. Rather than cyclically heating and cooling a gas like a classical engine, a quantum engine works by turning bosons into fermions and back again.
"To turn a fermion into a boson, you combine two fermions into a molecule. This new molecule is a boson. After breaking it down, we can get the fermion back again." Professor Thomas Busch, leader of the Quantum Systems Group, explained: "By doing this in a loop, we can power the engine without using heat."
The efficiency and potential of quantum engines
Although this engine only works in a quantum state, the research team found that it is quite efficient, reaching up to 25% in the existing experimental setup established by German collaborators.
This new engine is an exciting development in the field of quantum mechanics and has the potential to further advance the emerging field of quantum technologies. But does that mean we'll soon see quantum mechanics powering car engines? Keerthy Menon explains: "While these systems are very efficient, we have only done a proof-of-concept with experimental collaborators. There are many challenges to making a useful quantum engine."
The heat can destroy quantum effects if the temperature is too high, so researchers must keep the system as cold as possible. However, running experiments at such low temperatures requires a lot of energy in order to protect sensitive quantum states.
The next steps in the research will involve solving 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.