Ludwik KRANZ

Quantum computing is a frontier of technology that provides new tools for scientific research, gradually changing our perception of information processing capabilities. Ludwik Kranz is a physicist dedicated to developing silicon-based quantum computers, currently leading the Quantum Systems Engineering Team at Silicon Quantum Computing (SQC), a start-up company based at the University of New South Wales (UNSW). Ludwik and his team use a Scanning Tunnelling Microscope to place phosphorus (P) atoms into a silicon chip with atomic precision. They then perform quantum computation by controlling the spins of individual P atoms. Ludwik was one the pioneers to use atomic placement as a tool to build fully functional quantum processors, including the demonstration of the first qubit using this technology and the first two-qubit gate operating within only 0.8 nanoseconds - 200 times faster than other two-qubit gates at that time. 

One of the key bottlenecks limiting the performance of atom-based quantum computers is charge noise caused by defects in the material environment that hosts the qubits. To address this, Ludwik optimised the manufacturing process of quantum devices, reducing charge noise to an unprecedented low level (10 times lower than previous records), marking the lowest level of charge noise in any solid-state qubit platform. This reduction of noise minimised the qubit errors, allowing the team to now routinely achieve qubit error rates well below the required fault-tolerant threshold. 

Ludwik’s current research focuses on engineering silicon chips on the atomic scale, where the properties of the quantum processor can be optimised by controlling the exact arrangement of atoms in the device. Using this approach, a team led by Ludwik has recently demonstrated, for the first time, that silicon-based multi-qubit devices are capable of successfully executing complex, industry-relevant quantum computing algorithms. Moving forward, one of the challenges Ludwik sets for himself and his team is to demonstrate functional quantum error correction, which will require a large number of high-quality qubits.