Machines have shaped our lives since the Industrial Revolution. Over time, they have undergone a remarkable evolution, becoming more powerful, more efficient, and above all, smaller. Professor Artur Widera from the Department of Physics at RPTU is now exploring how microscopic machines might function in the quantum world – the realm of the smallest particles. As part of an ERC Advanced Grant from the European Union, his research on the "Quantum Engine" is being funded with 2.5 million euros. This funding scheme targets established leading researchers with an outstanding scientific track record who aim to open up new areas of research.
Quantum effects such as entanglement, interference, and quantum statistics could make machines more efficient or powerful. “However, the special laws of quantum physics can also hinder the performance of machines,” says Professor Artur Widera, who heads the Individual Quantum Systems department at the Rhineland-Palatinate Technical University of Kaiserslautern-Landau (RPTU). He will now receive €2.5 million in funding from the European Research Council (ERC) for five years for his research work as part of an ERC Advanced Grant. The funding line is aimed at established top researchers with an outstanding track record who want to open up new areas of research.
“We want to find out how quantum properties change the performance of microscopic machines, or more precisely, what the properties of microscopic machines in the quantum world look like and how they can be described,” says Widera, describing the research projects that will be funded. In addition, he and his team want to understand the fundamental mechanisms for the operation of machines from a technological perspective and tailor them to experimental implementations. “And we want to build machines, both single-atom machines and multi-particle machines, that operate according to the laws of quantum physics and both generate work and run autonomously.”
Operation of a single-atom machine demonstrated
In recent years, Artur Widera has been able to realize fundamental quantum mechanisms for the operation of such machines: “A classical machine works, for example, by periodically heating and cooling the working medium, such as fuel. We were able to replace this classical mechanism with fundamentally quantum mechanical mechanisms.”
Widera and his team have already been able to operate a single-atom machine in which the fuel is not in the form of thermal energy but in the form of spin polarization of a quantum bath. Widera and his team use ultra-cold atoms, which make it possible to control both individual atoms and quantum many-body systems very well.
In such systems, a machine can be operated by changing the volume of the container (the cylinder in a classic motor) for the working medium (a quantum gas or single atom) and periodically applying energy changes, as in a classic motor. “To study quantum effects, the bath can be prepared in a wide variety of quantum mechanical states and their influence on the performance of such a motor can be investigated.” In order to extract work from the machine, the excitation energy must be converted from atomic form into photonic and then into mechanical forms. “To ultimately ensure autonomous operation, feedback mechanisms must be developed and incorporated, but these must not destroy the actual quantum state.”
Fascinated by quantum systems
Widera describes the research project as virtually compelling. This is because increasing miniaturization—just think of computers, which are getting smaller and smaller—inevitably raises the question of “what the smallest machine can look like, what the absolute limit of efficiency is,” and whether quantum effects can be used to build a better machine.
How will this field of research develop over the next five to ten years? Researchers may succeed in “activating” quantum matter, opening up new ways in which quantum materials can self-organize or take on new phases of matter. As a non-physicist, one could imagine this as similar to a flock of birds: quantum particles that gather and move in the same direction. Artur Widera: “The vision is to build independently operating quantum motors whose special properties and applications we want to explore.” The physicist, who has been a professor in Kaiserslautern since 2010, is more than enthusiastic about his field of research: “Seeing the behavior of quantum systems still fascinates me completely.”