Quantum computers: Bar-Ilan University researchers develop superconducting flux qubits with unprecedented reproducibility

Dr. Michael Stern and co-workers from the Department of Physics and Quantum Entanglement Science and Technology (QUEST) Center at Bar-Ilan University in Israel are attempting to build superconducting processors based on a type of circuit called superconducting flux qubits. A flux qubit is a micron-sized superconducting loop where electrical current can flow clockwise or counter-clockwise, or in a quantum superposition of both directions. Contrary to transmon qubits, these flux qubits are highly non-linear objects and can thus be manipulated on very short time scales with high fidelity. The main drawback of flux qubits, however, is that they are particularly difficult to control and to fabricate. This leads to sizeable irreproducibility and has limited their use in the industry until now to quantum annealing optimization processes such as the ones realized by D-Wave.

Using a novel fabrication technique and state-of the-art equipment, a group led by Dr. Stern, in collaboration with Pr