In the recent Physics Review Letters for APS, School of Physics PhD student Chris Corlett, together with his supervisors Professor Noah Linden (School of Mathematics) and Dr. Paul Skrzypczyk (School of Physics), and collaborators in Oxford and Strathclyde, have introduced a powerful and general-purpose scheme for accelerating quantum measurements. Accurate and fast quantum measurements are crucial for the development of emerging quantum technologies, such as quantum metrology and computing. In particular, recent seminal results in quantum error correction demonstrate the need for fast, accurate measurements in order to facilitate error-decoding, without which fault-tolerance would be impossible. However, the accuracy of a measurement usually comes at the price of speed, leading to a seemingly fundamental challenge.

The new work shows how to overcome this. The novel idea behind the new scheme is to trade ‘space’ (i.e. the number of qubits used) for time. The scheme uses additional auxiliary qubits, all of which are then simultaneously measured for a briefer duration than a standard measurement, hence reducing total measurement time. Remarkably, this allows the quality of a measurement to be maintained, or even enhanced, even as it is sped up. The scheme is widely applicable to a broad range of leading quantum hardware platforms, including cold atoms, trapped ions and superconducting qubits.

As the global race to build the highest performance quantum technologies continues, the scheme has the potential to become a standard part of the quantum read-out process.