Author:
Yang Tian-Yu,Wang Xiang-Bin
Abstract
AbstractGaussian boson sampling (GBS) plays a crucially important role in demonstrating quantum advantage. As a major imperfection, the limited connectivity of the linear optical network weakens the quantum advantage result in recent experiments. In this work, we introduce an enhanced classical algorithm for simulating GBS processes with limited connectivity. It computes the loop Hafnian of an $$n \times n$$
n
×
n
symmetric matrix with bandwidth w in $$O(nw2^w)$$
O
(
n
w
2
w
)
time. It is better than the previous fastest algorithm which runs in $$O(nw^2 2^w)$$
O
(
n
w
2
2
w
)
time. This classical algorithm is helpful on clarifying how limited connectivity affects the computational complexity of GBS and tightening the boundary for achieving quantum advantage in the GBS problem.
Funder
National Natural Science Foundation of China
Taishan Scholars Program, China
Publisher
Springer Science and Business Media LLC