Pulse-level noisy quantum circuits with QuTiP

TL;DR

This paper presents pulse-level simulation tools for noisy quantum circuits in QuTiP, enabling detailed modeling of noise effects and control optimization for various quantum processors, advancing NISQ computing research.

Contribution

Introduction of new pulse-level simulation tools in QuTiP's qutip-qip package for modeling noise and control in quantum circuits, with practical examples and integration capabilities.

Findings

Simulated Deutsch-Jozsa algorithm on different quantum processors.

Modeled cross-talk noise in ion-trap systems.

Reproduced Ramsey experiments with Lindblad dynamics.

Abstract

The study of the impact of noise on quantum circuits is especially relevant to guide the progress of Noisy Intermediate-Scale Quantum (NISQ) computing. In this paper, we address the pulse-level simulation of noisy quantum circuits with the Quantum Toolbox in Python (QuTiP). We introduce new tools in qutip-qip, QuTiP's quantum information processing package. These tools simulate quantum circuits at the pulse level, leveraging QuTiP's quantum dynamics solvers and control optimization features. We show how quantum circuits can be compiled on simulated processors, with control pulses acting on a target Hamiltonian that describes the unitary evolution of the physical qubits. Various types of noise can be introduced based on the physical model, e.g., by simulating the Lindblad density-matrix dynamics or Monte Carlo quantum trajectories. In particular, the user can define environment-induced decoherence at the processor level and include noise simulation at the level of control pulses. We illustrate how the Deutsch-Jozsa algorithm is compiled and executed on a superconducting-qubit-based processor, on a spin-chain-based processor and using control optimization algorithms. We also show how to easily reproduce experimental results on cross-talk noise in an ion-based processor, and how a Ramsey experiment can be modeled with Lindblad dynamics. Finally, we illustrate how to integrate these features with other software frameworks.