How much entanglement is needed for quantum error correction?
Abstract
It is commonly believed that logical states of quantum error-correcting codes have to be highly entangled such that codes capable of correcting more errors require more entanglement to encode a qubit. Here, we show that the validity of this belief depends on the specific code and the choice of entanglement measure. To this end, we characterize a tradeoff between the code distance quantifying the number of correctable errors, and the geometric entanglement measure of logical states quantifying their maximal overlap with product states or more general ``topologically trivial" states. The maximum overlap is shown to be exponentially small in for three families of codes: (1) low-density parity check codes with commuting check operators, (2) stabilizer codes, and (3) codes with a constant encoding rate. Equivalently, the geometric entanglement of any logical state of these codes grows at least linearly with . On the opposite side, we also show that this distance-entanglement tradeoff does not hold in general. For any constant and (number of logical qubits), we show there exists a family of codes such that the geometric entanglement of some logical states approaches zero in the limit of large code length.
Cite
@article{arxiv.2405.01332,
title = {How much entanglement is needed for quantum error correction?},
author = {Sergey Bravyi and Dongjin Lee and Zhi Li and Beni Yoshida},
journal= {arXiv preprint arXiv:2405.01332},
year = {2025}
}