A chessboard made of quantum dots – wissenschaft.de

In today’s computer technology, several billion transistors are controlled by a few thousand electrical paths. This is not yet possible in the field of quantum technologies. Until now, quantum dots that contain the building blocks of quantum computers, called qubits, had to be manipulated individually via their control electronics. But researchers at the QuTech Institute, a collaboration between Delft University of Technology and the Netherlands Organization for Applied Scientific Research, have made a breakthrough.

Inspired by the chessboard structure, the scientists arranged 16 quantum dots in a square so that each point could be clearly identified and controlled as in a coordinate system with a combination of horizontal and vertical wire. This so-called 4×4 matrix is ​​currently the largest controllable arrangement of quantum dots on a chip. The photo shows an image of the chip with an integrated checkerboard shape.

“This new method of quantum dot processing is useful for expanding systems to many qubits,” explains Francesco Borsoy, lead author of the results published in Nature Nanotechnology. “If each individual qubit were read from its control path, millions of wires would be needed for millions of qubits. However, with our chessboard-like system, millions of qubits could be controlled by only a few thousand wires, in a ratio similar to that in Ordinary computer chips.

By reducing the number of lines in quantum dot arrays, scientists are getting closer to producing quantum systems with a scalable number of qubits. The development is an important step on the path toward quantum computers, which are expected to require millions of qubits. QuTech researchers were only recently able to show that the germanium quantum dots they used provide results with a resolution previously unattainable in quantum dot systems and, when arranged as an array, can be successfully used in quantum simulations.

“It is exciting to see that we have taken some steps in scaling up to larger systems, improving performance and opening up new possibilities for quantum computers and simulators,” explains final author and head of research Menno Veldhorst. “The question remains to what extent we can create these checkerboard circuits, and if there Limit,whether we can connect multiple circuits to build larger circuits.

© Wissenschaft.de – Aurelia Eberhard