Continuous variable quantum computing
An alternative approach to discrete quantum bits is to use a large number of states of a harmonic oscillator to encode the values 0 and 1 of a logical qubit into complex superpositions of harmonic states. This approach is referred to as continuous-variable quantum computing. We explore continuous variable quantum computing in 3d- and planar microwave resonators. Our superconducting 3d cavities provide state-of-the-art quality factors and long-living photon states allowing us to encode quantum information in multi-photon states. This makes it possible to implement hardware-efficient quantum error correction while keeping the noise channels limited. We are currently actively investigating these directions.
Propagating Wigner-negative states generated from the steady-state emission of a superconducting qubit
Y. Lu, I. Strandberg, F. Quijandría, G. Johansson, S. Gasparinetti, and P. Delsing, Propagating Wigner-Negative States Generated from the Steady-State Emission of a Superconducting Qubit, Phys. Rev. Lett. 126, 253602 (2021).
Universal Gate Set for Continuous-Variable Quantum Computation with Microwave Circuits
T. Hillmann, F. Quijandriá, G. Johansson, A. Ferraro, S. Gasparinetti, and G. Ferrini, Universal Gate Set for Continuous-Variable Quantum Computation with Microwave Circuits, Physical Review Letters 125, (2020).
High quality three-dimensional aluminum microwave cavities
M. Kudra, J. Biznárová, A. Fadavi Roudsari, J. J. Burnett, D. Niepce, S. Gasparinetti, B. Wickman, and P. Delsing, High Quality Three-Dimensional Aluminum Microwave Cavities, Applied Physics Letters 117, (2020).