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

  • 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.

A superconducting circuit with movable elements

Positions

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

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

  • Ground-state cooling of a mechanical oscillator by a noisy environment
    C. Wang, L. Banniard, K. Børkje, F. Massel, L. de Lepinay, M. Sillanpää
    Nature Communications 15, 7395 (2024)

  • Quantum Reference Frames on Finite Homogeneous Spaces
    J. Glowacki, L. Loveridge, J. Waldron
    Int. J. Theor. Phys. 63, 137 (2024)

  • Hybrid optomechanical superconducting qubit system
    J. Manninen, R. H. Blick, F. Massel
    Phys. Rev. Res. 6, 023029 (2024)

  • Semiclassical dynamics of a superconducting circuit: chaotic dynamics and fractal attractors
    D. Stirpe, J. Manninen, F. Massel
    Physica Scripta 99, 075979 (2024)

  • Proposal for observing nonclassicality in highly excited mechanical oscillators by single photon detection
    K. R. Bush, K. Børkje
    Phys. Rev. A 109, 043505 (2024)

  • Measurement disturbance and conservation laws in quantum mechanics
    M. H. Mohammady, T. Miyadera, and L. Loveridge
    Quantum 7, 1033 (2023)

  • 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)

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)

  • 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)

Group leader

Members

PhD candidates