Quantum Technology - Research Group

Technological developments enable us to manipulate and control quantum effects at an increasingly advanced level of sophistication. This gives new opportunities, e.g., within communication, metrology, sensors, simulation and computation. Quantum technology will affect global communication networks and security on the internet.

Research areas

A superconducting circuit with movable elements

  • Mechanical systems in the quantum regime
    Our research involves theoretical studies of optomechanical or electromechanical setups with a focus on controlling micromechanical oscillators in the quantum regime, motivated in part by applications such as accurate sensing or quantum signal processing. We are also interested in the interplay of mechanical and transport properties in low-dimensional materials, e.g., graphene or topological materials.
  • Macroscopic nonclassicality
    We are interested in nonclassicality witnesses, in particular for revealing quantum behaviour of systems excited to large numbers of quanta, i.e., high-intensity electromagnetic fields, or of mechanical degrees of freedom at the mesoscopic or macroscopic mass scale. This is motivated both by realization of robust quantum applications as well as fundamental issues, such as alternative theories of decoherence or the relation between quantum mechanics and gravity.Operational view on quantum measurements
  • Foundations of quantum mechanics
    Much of our research in this area is centred around quantum measurements: weak measurements, sequential measurements, symmetry-constraints, incompatibility. Other interests include the quantum-classical transition, quantum reference frames, contextuality, and general probabilistic theories.


Please feel free to contact us if you are interested in our research.

At the moment, we do not have open PhD or postdoc positions.

We may be able to welcome exchange students who wish to write their Master thesis with us. Please get in touch if this is of interest to you.

External funding

Our group has received funding through QuantERA - a European Research Area Network (ERA-NET) Cofund Programme in the field of Quantum Technologies. USN participates in two QuantERA projects: QuaSeRT (Optomechanical quantum sensors at room temperature, 2018-2021) and MQSens (Quantum sensing with nonclassical mechanical oscillators, 2022-2025).


Recent publications

  • Non-Hermitian topological quantum states in a reservoir-engineered transmon chain
    W. Brzezicki, M. Silveri, M. Płodzień, F. Massel, and T. Hyart, Phys. Rev. B 107, 115146 (2023)

  • Quantum state purity versus average phonon number for characterization of mechanical oscillators in cavity optomechanics
    K. Børkje, F. Marin, Phys. Rev. A 107, 013502 (2023)

  • Mechanical Detection of the De Haas−van Alphen Effect in Graphene
    J. Manninen, A. Laitinen, F. Massel, P. Hakonen, Nano. Lett. 22, 9869 (2022)

  • Two-dimensional quantum motion of a levitated nanosphere
    A. Ranfagni, K. Børkje, F. Marino, F. Marin, Phys. Rev. Research 4, 033051 (2022)

  • Incompatibility of effects in general probabilistic models
    R. Beneduci. L. Loveridge, J. Phys. A: Math. Theor. 55 254005 (2022)

  • Nonclassical photon statistics in two-tone continuously driven optomechanics
    K. Børkje, F. Massel, J.G.E. Harris, Phys. Rev. A 104, 063507 (2021)

  • A quantum reference frame size-accuracy trade-off for quantum channels
    T. Miyadera, L. Loveridge, J. Phys.: Conf. Ser. 1638 012008 (2020)

Selected publications

  • Backaction-evading measurement of entanglement in optomechanics
    F. Massel, Phys. Rev. A 100, 023824 (2019)

  • Heterodyne photodetection measurements on cavity optomechanical systems: Interpretation of sideband asymmetry and limits to a classical explanation,
    K. Børkje, Phys. Rev. A 94, 043816 (2016)

  • Position Measurements Obeying Momentum Conservation,
    P. Busch and L. Loveridge, Phys. Rev. Lett. 106, 110406 (2011)

  • Quantum theory of successive projective measurements,
    L. M. Johansen, Phys. Rev. A 76, 012119 (2007)

  • Single-photon optomechanics,
    A. Nunnenkamp, K. Børkje, S.M. Girvin, Phys. Rev. Lett. 107, 063602 (2011)

  • Stabilized entanglement of massive mechanical oscillators,
    C. F. Ockeloen-Korppi, E. Damskägg, J. M. Pirkkalainen, M. Asjad, A. A. Clerk, F. Massel, M. J. Woolley, M. A. Sillanpää, Nature 556, 478 (2018)

  • Symmetry, Reference Frames and Relational Quantities in Quantum Mechanics,
    L. Loveridge, T. Miyadera and P. Busch. Found. Phys. 48, 2 (2018)

  • Weak measurements with arbitrary probe states,
    L. M. Johansen, Phys. Rev. Lett. 93, 120402 (2004)