Trajectory-independent speed limits for controlled open quantum systems

TL;DR

This paper derives schedule-independent quantum speed limits for open quantum systems described by Lindblad equations, providing fundamental bounds on quantum annealing times that account for dissipation and control.

Contribution

It generalizes schedule-independent quantum speed limits from closed to open systems, incorporating dissipation effects in quantum annealing bounds.

Findings

Derived lower bounds for quantum annealing times in open systems

Bounds capture key scaling with dissipation strength

Applied bounds to thermal state preparation in Ising models

Abstract

Existing quantum speed limits for controlled open quantum systems depend on the specified trajectory. For example, lower bounds on quantum annealing times in the presence of dissipation depend explicitly on the chosen annealing schedule. Recently, schedule-independent speed limits have been derived for annealing in the closed quantum system setting (SciPost Phys. 18, 159 (2025)). In this work, we generalize these results to open quantum systems, deriving schedule-independent lower bounds for quantum annealing times in systems described by a Lindblad master equation. We analyze the interplay between coherent control and dissipation in single- and two-qubit examples, demonstrating that the derived lower bounds capture key scaling behavior with respect to the strength of the dissipator. Finally, we apply the bound to thermal state preparation and show that the bound matches the expected asymptotic behavior for an Ising model in the high temperature limit.