Researchers in Netherlands Build 2D Array of Four Qubits in Milestone for Scalable Quantum Computing

(EENewsEurope) Researchers in The Netherlands have built a 2D array of four qubits in a crucial milestone for scalable quantum computer technology. The group at QuTech, a collaboration between TU Delft and TNO, is led by of Menno Veldhorst and has built a four qubit array using germanium quantum dots.
“By putting four such qubits in a two-by-two grid, demonstrating universal control over all qubits, and operating a quantum circuit that entangles all qubits, we have made an important step forward in realizing a scalable approach for quantum computation,” said Veldhorst.
Electrons trapped in quantum dots have been studied for more than two decades as a platform for quantum information but scaling beyond two-qubit logic has remained elusive. To break this barrier, the groups of Menno Veldhorst and Giordano Scappucci decided to take an entirely different approach and started to work with holes (i.e. missing electrons) in germanium. Using this approach, the same electrodes needed to define the qubits could also be used to control and entangle them.