Associate professor Witlef Wieczorek from Chalmers University of Technology, alongside colleagues from four European partners, have gotten their project “SuperMeQ” funded within the EU Basic Science for Quantum Technologies call.
“We look very much forward to make our project a success, and to join forces to attack important problems in the basic science underpinning quantum technologies”, says Witlef Wieczorek, who will coordinate the project.
Quantum technologies are expected to transform digital technologies. This has led to strong world-wide support in research and innovation actions into this field, such as the European Quantum Technology Flagship and, in Sweden, the Wallenberg Centre for Quantum Technology (WACQT).
So far quantum control can be exerted over atoms, ions, photons, and superconducting circuits, amongst others. These physical systems underpin the current advancement and near-term deployment of sophisticated quantum technologies.
The SuperMeQ project will target a physical system that has only recently been added to the quantum hardware: the motional degree of freedom of mechanical resonators *.
“The center-of-mass motion * of mechanical resonators is susceptible to external forces or accelerations and, thus, an appealing degree of freedom for building novel sensing technologies”, says Witlef Wieczorek. “This can for instance concern detecting the weak gravitational force between small objects or detecting potential dark matter candidates. Preparing this degree of freedom in quantum states could result in the development of novel quantum sensors which would outperform conventional sensing approaches.”
A clever experimental idea
Yet, it is known that any quantum advantage is hampered by the undesired, unavoidable and to a great extent uncontrollable coupling to the environment, resulting in decoherence * of quantum states and, thus, the loss of quantumness. Witlef Wieczorek explains that SuperMeQ will minimize decoherence by using a clever experimental idea.
“We will levitate a superconducting microparticle in vacuum. This experimental arrangement will minimize known sources of decoherence. However, SuperMeQ may encounter unexpected or unconventional sources of decoherence, which would be a highly relevant scientific finding.”
A key in SuperMeQ is the coupling of the center-of-mass motion of the mechanical resonators to superconducting quantum circuit technology. This experimental architecture will allow Witlef Wieczorek and his colleagues to exert quantum control over the mechanical resonators in the first place.
Explore ways to increase coupling strength
“It is important that this coupling is sufficiently strong to be able to generate quantum states in the mechanical resonators”, he says. “Another major focus of SuperMeQ is therefore to explore ways to increase this coupling strength. For this part, we will develop specifically engineered magnetic or superconducting micromechanical resonators and exploit inductive coupling schemes, which can outperform the conventionally used capacitive coupling schemes as used, for example, in superconducting quantum computers.”
The researchers aim to contribute to the widening of our understanding of limits of quantum control. For example, decoherence and coupling strength both place limits to quantum control and, thus, can hamper a wide deployment of quantum technologies.
Better understanding of decoherence
“SuperMeQ will contribute to a better understanding of decoherence mechanisms of more macroscopic objects, which is of fundamental scientific interest”, says Witlef Wieczorek. “Furthermore, we aim at lying the foundation for the development of next generation quantum sensors based on mechanical resonators, which may find applications in fundamental research and technological applications.”
The project started 1 October 2022, and Witlef Wieczorek has already hired a PhD student that will work within the SuperMeQ project.
“It is key for me to give the student a good start within the project. Furthermore, among our first tasks are to get the project website going and to organize our project kick-off, which will be a hybrid meeting taking place in Barcelona on 10 and 11 of November.”
About SuperMeQ
SuperMeQ (acronym for “Exploring nonclassical states of center-of-mass mechanical motion with superconducting magneto- and levitomechanics") is an EU project that encompasses eight PI:s from five European partners: Chalmers University of Technology, Austrian Academy of Sciences (Austria), Walther-Meissner-Institute (Germany), Karlsruhe Institute of Technology (Germany) and Universidade Autonoma de Barcelona (Spain).
The project is coordinated by Witlef Wieczorek, associate professor at Chalmers University of Technology. The project started 1st October and runs for four years.
SuperMeQ aims to make three major scientific contributions to the basic science underpinning quantum technologies when utilizing the center-of-mass degree of freedom of mechanical resonators:
1: Understanding and minimizing decoherence processes of massive mechanical resonators,
2: Engineering a stronger vacuum coupling rate between a mechanical resonator and a superconducting microwave cavity *,
3: Studying practical and fundamental limits in generating nonclassical states of massive objects and their exploration for quantum-enhanced sensing tasks.
Furthermore, SuperMeQ aims at educating researchers in the field of quantum technologies and making its developed technology available for activities within the European Quantum Flagship.
More information about SuperMeQ (official website)
Contact
Witlef Wieczorek
Associate Professor, The Department of Microtechnology and Nanoscience
witlef.wieczorek@chalmers.se, +46317726772
* Short glossary
Mechanical resonator: A device which exploits mechanical vibrations, for instance the tip in an atomic force microscope. A music drum is basically a mechanical resonator.
Center-of-mass motion: The center-of-mass motion of a mechanical resonator can be compared to the movement of a child on a swing: the swing moves back and forth around it’s center-of-mass. In SuperMeQ, we use the center-of-mass motion of a levitated particle, which is moving back and forth in a magnetic trap. We also use the center-of-mass motion of atomic force microscope-like mechanical resonators.
Decoherence: The process that causes a quantum state, for example a superposition or entangled state, to decay and collapse. The result is in most cases a loss of any quantum advantage.
Cavity: A cavity confines microwave photons within a fixed spatial region. In can be thought of as bouncing the microwave photons back and forth and thus enabling a stronger interaction between the photons and, in our case, the center-of-mass motion of the mechanical resonators we use.
Text: Robert Karlsson
Illustration: Yen Strandqvist
- Head of Division, Quantum Technology, Microtechnology and Nanoscience