Distance-based measures and Epsilon-measures for measurement-based quantum resources
Arindam Mitra, Sumit Mukherjee, Changhyoup Lee
TL;DR
This work develops a unified, distance-based approach to quantify measurement-based quantum resources when access to states or measurements is imperfect. It defines a distance between sets of measurements $\widetilde{\mathcal{D}}$ and builds a corresponding distance-based resource measure $\overline{\mathbbm{R}}$ from a generic distance $\mathbb{D}$, together with $\varepsilon$-measures $\mathbbm{R}^{\mathbbm{D}}_{inf,\varepsilon}$ that quantify robustness under partial knowledge. The authors prove key properties including monotonicity, convexity, and contractivity under free transformations for the $\varepsilon$-measures, and relate these quantities to one-shot dilution cost $\mathbbm{C}^{\mathcal{Z}}_{\epsilon}$ and distillable resource $\mathbbm{E}^{\mathcal{Z}}_{\epsilon}$ as well as smooth asymptotic measures $\mathbbm{C}^{\infty}_{l}$ and $\mathbbm{C}^{\infty}_{u}$. The framework applies to both single-measurement resources (e.g., coherence, sharpness) and set-based resources (e.g., incompatibility), providing a general toolkit for developing measurement-based resource theories and analyzing operational tasks.
Abstract
Quantum resource theories provide a structured and elegant framework for quantifying quantum resources. While state-based resource theories have been extensively studied, their measurement-based resource theories remain relatively underexplored. In practical scenarios where a quantum state or a set of measurements is only partially known, conventional resource measures often fall short in capturing the resource content. In such cases, ε-measures offer a robust alternative, making them particularly valuable. In this work, we investigate the quantification of measurement-based resources using distance-based measures, followed by a detailed analysis of the mathematical properties of ε-measures. We also extend our analysis by exploring the connections between ε-measures and some key quantities relevant to resource manipulation tasks. Importantly, the analysis of resources based on sets of measurements are tedious compared to that of single measurements as the former allows more general transformations such as controlled implementation. Yet our framework applies not only to resources associated with individual measurements but also to those arising from sets of measurements. In short, our analysis is applicable to existing resource theories of measurements and has the potential to be useful for all resource theories of measurements that are yet to be developed.