Group seminar at MPQ and Zoom: Demonstration of logical qubits and repeated error correction with better-than-physical error rates

Linnea Grans-Samuelsson, Univesity of Oxford, UK
Group seminar at MPQ lecture hall and Zoom
Tuesday, 23 September, 09:00am (MEZ)

The promise of quantum computers hinges on the ability to scale to large system sizes, e.g., to run quantum computations consisting of more than 100 million operations fault-tolerantly. This in turn requires suppressing errors to levels inversely proportional to the size of the computation. Error suppression can be achieved through the use of quantum error-correcting codes, where logical qubits are encoded among many physical qubits. In this talk I discuss a recent experiment performed by Microsoft and Quantinuum, where we demonstrated better-than-physical logical performance using a quantum error-correcting [[12,2,4]] code based on Knill's C4/C6 scheme, operated on a trapped-ion QCCD processor. Notably, we were able to demonstrate that the logical error rate per error correction cycle was lower than the corresponding physical baseline. I discuss the choices we made for which code to use and how to implement it, based on the goals of the experiment and the constraints from the hardware.