New quantum code cuts gate count for error correction in half

Researchers at Yale University have developed a new quantum code that halves the gate count of the fastest encoder known previously for surface codes. This advancement addresses a critical challenge in building practical quantum computers by streamlining the process of preparing logical states within quantum error correction codes. The work proposes a non-local unitary circuit based on code conversion between rotated and regular surface codes, enabling more space-time efficient realization of surface code eigenstates like the Pauli Y-eignestate and Clifford eigenstates. They define a regular surface code of size d as Reg(d) and a rotated surface code as Rot(d), noting that a rotated code of the same distance requires fewer data qubits. They perform numerical simulations to benchmark the performance of their encoder against a previous local unitary encoder and the conventional stabilizer-measurement based encoder for…