Quantitative Convergence and Spectral-Projector Stability for Finite-Dimensional GKSL Semigroups, with Illustrations on Truncated Bosonic Models
Geraldo José Ferraresi de Araújo
Abstract
We develop a quantitative framework for analyzing convergence and spectral-projector stability in finite-dimensional open quantum systems governed by Gorini-Kossakowski-Sudarshan-Lindblad (GKSL) dynamics. Our focus is on computable bounds for the approach to the asymptotic sector and on perturbative stability estimates for the associated spectral projection. Rather than claiming universal constants for arbitrary Lindbladians, we formulate our results under explicit spectral-separation and resolvent assumptions, thereby making the role of non-normality transparent. We distinguish two geometrically different cases: (i) primitive semigroups with a unique steady state, and (ii) non-primitive semigroups with multidimensional steady-state structure relevant to encoded quantum information. We then illustrate the framework on truncated bosonic models motivated by dissipatively stabilized cat-qubit memories. This repository contains: (1) the preprint manuscript (v1.1) with Appendices A–C; (2) a Python validation suite implementing computation of resolvent norms, spectral gaps, projector stability, and primitivity detection; (3) 41 validated tests covering Propositions 1–2, Frigerio criterion, noise bias, and truncation error; (4) four numerical experiments on truncated bosonic models with publication-quality figures; (5) reproducible numerical results with checksums.