Calderbank-Shor-Steane holographic quantum error-correcting codes

We expand the class of holographic quantum error-correcting codes by developing the notion of block perfect tensors, a wider class that includes previously defined perfect tensors. The relaxation of this constraint opens up a range of other holographic codes. We demonstrate this by introducing the self-dual Calderbank-Shor-Steane (CSS) heptagon holographic code, based on the 7-qubit Steane code. Finally, we show promising thresholds for the erasure channel by applying a straightforward, optimal erasure decoder to the heptagon code and benchmark it against existing holographic codes.