The scalability of photonic implementations of fault-tolerant quantum computing based on Gottesman-Kitaev-Preskill (GKP) qubits is injured by the requirements of inline squeezing and reconfigurability of the linear optical network. In this work we propose a topologically error-corrected architecture that does away with these elements at no cost - in fact, at an advantage - to state preparation overheads. Our computer consists of three modules: a 2D array of probabilistic sources of GKP states; a depth-four circuit of static beamsplitters, phase shifters, and single-time-step delay lines; and a 2D array of homodyne detectors. The symmetry of our proposed circuit allows us to combine the effects of finite squeezing and uniform photon loss within the noise model, resulting in more comprehensive threshold estimates. These jumps over both architectural and analytical hurdles considerably expedite the construction of a photonic quantum computer.
@article{arxiv.2104.03241,
title = {Fault-tolerant quantum computation with static linear optics},
author = {Ilan Tzitrin and Takaya Matsuura and Rafael N. Alexander and Guillaume Dauphinais and J. Eli Bourassa and Krishna K. Sabapathy and Nicolas C. Menicucci and Ish Dhand},
journal= {arXiv preprint arXiv:2104.03241},
year = {2021}
}
Comments
15 pages, 6 figures, comments welcome; minor typos corrected and Fig. 2 updated to resolve rendering issues on some platforms