Programmable Open Quantum Systems

TL;DR

This paper introduces a framework for quantifying and characterizing the programmability of open quantum systems, specifically Lindbladian semigroups, with implications for quantum control and resource estimation.

Contribution

It develops a novel framework combining retrieval maps and program states to analyze Lindbladian programmability, identifying classes enabled by symmetry and stochastic structure.

Findings

Identifies quantum programmable classes like covariant semigroups and dissipative Pauli Lindbladians.

Provides necessary conditions that exclude certain generators from being physically programmable.

Introduces an operational programming cost measure with properties like continuity and faithfulness.

Abstract

Programmability is a unifying paradigm for enacting families of quantum transformations via fixed processors and program states, with a fundamental role and broad impact in quantum computation and control. While there has been a shift from viewing open systems solely as a source of error to treating them as a computational resource, their programmability remains largely unexplored. In this work, we develop a framework that characterizes and quantifies the programmability of Lindbladian semigroups by combining physically implementable retrieval maps with time varying program states. Within this framework, we identify quantum programmable classes enabled by symmetry and stochastic structure, including covariant semigroups and fully dissipative Pauli Lindbladians with finite program dimension. We further provide a necessary condition for physical programmability that rules out coherent generators and typical dissipators generating amplitude damping. For such nonphysically programmable cases, we construct explicit protocols with finite resources. Finally, we introduce an operational programming cost, defined via the number of samples required to program the Lindbladian, and establish its core structural properties, such as continuity and faithfulness. These results provide a notion of programming cost for Lindbladians, bridge programmable channel theory and open system dynamics, and yield symmetry driven compression schemes and actionable resource estimates for semigroup simulation and control in noisy quantum technologies.