Advancing the practical implementation of quantum error correction with fault-tolerant syndrome extraction

Quantum computers are a new type of powerful computer, based on building blocks called quantum bits, or qubits, that carry information in a more effective way than bits on a conventional computer. However, both bits and qubits can be affected by errors that change the information they contain.

For quantum computers to perform complex calculations accurately and become commercially useful, we need to be able to 'correct' these errors. This is the biggest bottleneck in quantum computing. When solved, it will be the turning point in the quantum industry, turning quantum computers into extremely powerful machines. But it is not that simple. According to quantum mechanics, every time we try and 'read' a qubit, the information gets destroyed. We therefore need to use a second group of qubits that will tell us if and where an error occurred without disturbing the qubits carrying the original information. However, collecting this indirect information -- a process called syndrome extraction - can introduce errors too.

We will solve this challenge by developing codes to perform syndrome extraction in the most accurate way possible. We'll then test these codes on a real quantum computer. In this project, the UK's leading quantum software company, Riverlane, will work closely with Rigetti, a company developing quantum computers based on superconducting circuits. Rigetti owns the most powerful quantum machine in the UK, which will feature 80 qubits in early 2023\. We will work together to combine quantum software and hardware to take a first big step in implementing error correction in quantum computers. This is the only way for quantum computers to become powerful and stable enough to solve real-world problems that require complicated computations. Our project brings together the best UK companies in quantum software and hardware able to deliver on this task. Our work will strengthen the UK quantum industry and accelerate the production of quantum computers that will transform several industries, such as drug discovery and materials development.