Title
Computational power of one- and two-dimensional dual-unitary quantum circuits.
Abstract
Quantum circuits that are classically simulatable tell us when quantum computation becomes less powerful than or equivalent to classical computation. Such classically simulatable circuits are of importance because they illustrate what makes universal quantum computation different from classical computers. In this work, we propose a novel family of classically simulatable circuits by making use of dual-unitary quantum circuits (DUQCs), which have been recently investigated as exactly solvable models of non-equilibrium physics, and we characterize their computational power. Specifically, we investigate the computational complexity of the problem of calculating local expectation values and the sampling problem of one-dimensional DUQCs, and we generalize them to two spatial dimensions. We reveal that a local expectation value of a DUQC is classically simulatable at an early time, which is linear in a system length. In contrast, in a late time, they can perform universal quantum computation, and the problem becomes a BQP-complete problem. Moreover, classical simulation of sampling from a DUQC turns out to be hard.
Year
DOI
Venue
2022
10.22331/q-2022-01-24-631
Quantum
DocType
Volume
Citations 
Journal
6
0
PageRank 
References 
Authors
0.34
0
3
Name
Order
Citations
PageRank
Ryotaro Suzuki121.69
Kosuke Mitarai200.34
Keisuke Fujii365.56