Provided is a quantum computing device comprising a carbon nanotube, a superconducting substrate in quantum proximity to the nanotube and being in a superconducting state having a pairing correlation matrix with a substantial spin-triplet component in a direction perpendicular to the nanotube, and a magnet arranged to provide a longitudinal magnetic field along a longitudinal axis of the nanotube. Further provided is a quantum computing device comprising at least three substrates made of a superconductor material and each in a superconducting state, and a non-superconducting structure made of a material in which the electrons' closed trajectories experience strong spin-orbit coupling interactions and being in quantum proximity to the substrates. The sum of the phase differences between the order parameters of all of the substrates is at least π.