Year: 2022
Type: article
Abstract: We provide an efficient algorithm to compile quantum circuits for fault-tolerant execution.We target surface codes, which form a two-dimensional grid of logical qubits with nearest-neighbor logical operations.Embedding an input circuit's qubits in surface codes can result in long-range two-qubit operations across the grid.We show how to prepare many long-range Bell pairs on qubits connected by edge-disjoint paths of ancillae in constant depth that can be used to perform these long-range operations.This forms one core part of our edge-disjoint path compilation (EDPC) algorithm, by easily performing many parallel long-range Clifford operations in constant depth.It also allows us to establish a connection between surface code compilation and several well-studied edge-disjoint path problems.Similar techniques allow us to perform non-Clifford single-qubit rotations far from magic state distillation factories.In this case, we can easily find the maximum set of paths by a max-flow reduction, which forms the other major part of EDPC.EDPC has the best asymptotic worst-case performance guarantees on the circuit depth for compiling parallel operations when compared to related compilation methods based on SWAP gates and network coding.EDPC also shows a quadratic depth improvement over sequential Pauli-based compilation for parallel rotations requiring magic resources.We implement EDPC and find significantly improved performance for circuits built from parallel controlled-NOT (CNOT) gates, and for circuits that implement the multicontrolled X gate C k NOT.
Source: PRX Quantum
Language: English
Subfield: Artificial Intelligence
Field: Computer Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,450
OpenAlex ID: W3209549234