Applications of superconducting qubits
Superconducting qubit research has a long tradition in Finland, currently pursued by 6 research groups at Aalto. Although Finland has not yet started a large-scale effort to build a superconducting quantum computer, the research groups have demonstrated successful measurement and control protocols for individual qubits and pursue significant efforts in this direction. The techniques may prove useful in an eventual large-scale quantum computer and other shorter-term applications, such as tunable microwave components. The controlled generation of entangled electron spins is also being pursued based on the splitting of Cooper pairs between a superconductor and normal-state electrodes.
Research groups: KVANTTI, PICO, NANO, NEMS, QT, QCD.
Quantum reservoir engineering and heat management
Open quantum systems and mesoscopic heat transport have been successfully studied in Finland as a pioneering field, which currently includes 6 research groups at Aalto. With the recent rise of electric quantum devices, this basic knowledge has become invaluable for solving several outstanding problems, such as the interplay between dissipation and external control to guarantee extreme precision in quantum control, precise initialization of chosen quantum degrees of freedom, and quasiparticle and local phonon refrigeration. In a large-scale quantum computer, there will be a lot of power dissipated at the chip level which calls for these studies on how to, nevertheless, keep the chip at low phonon temperatures, and how to initialize the quantum degrees of freedom to even lower temperatures than the phonons. Further, the fidelity of quantum sensors could be greatly improved by accurate initialization.
Research groups: PICO, QCD, MSP, QT, Sabrina Maniscalco group, Engineered nanosystems.
Applications of quantum thermodynamics
Although the electrical degrees of freedom are very well in control of current technologies, the precise control of thermal flows and implementation of high-efficiency thermal engines has lagged behind greatly. The solution to this problem is to be found at the nanoscale, a subject where Finnish researchers have recently excelled in the thermodynamics of small electrical systems, covered by 5 research groups at Aalto. This is an exceptional knowledge base to implement quantum thermodynamic systems and engines. The potential applications are the realizations of high-efficiency heat engines working at low-temperature gradients and efficient energy-harvesting devices.
Research groups: PICO, QT, MSP, Erik Aurell group, Engineered nanosystems.
Topological materials
Topology is a very powerful tool to describe the qualitative behavior of physical systems and provides the foundations for a topological quantum computer. Topology in condensed matter quantum systems has been studied for several decades in Finland, starting from the pioneering work on superfluid helium in rotation and continuing to directions with promising future applications, such as flat-band high-temperature superconductivity. Recently, there has been breakthrough theory work in Finland discovering a connection between flat-band superfluidity and quantum geometry, connecting superfluid weight with the Chern number. Currently, there are 4 research groups at Aalto working on topological materials and defects.
Research groups: NANO, QD, ROTA, QCD.
