New methods for reducing resource overhead in the surface code

The surface code is one of the most promising quantum error-correcting codes due to its tolerance to high error rates. However, it is relatively qubit inefficient, requiring very many qubits to hit target logical error rates. One proposal to lower this overhead is to use a hierarchical coding scheme, with surface codes concatenated into more qubit-efficient codes. We will discuss one such approach towards reducing these overheads.