Macroscopic states and operations: a generalized resource theory of coherence

Macroscopic states and operations: a generalized resource theory of coherence

Seminar author:Teruaki Nagasawa

Event date and time:03/17/2025 02:30:pm

Event location:Seminar Room, GIQ

Event contact:

Coarse-graining plays a crucial role in explaining irreversible phenomena. For example, macroscopic states can be seen as coarse-grained representations, and from experience we know that irreversible processes, such as the increase of thermodynamic entropy, occur. In other words, macroscopic states correspond to coarse resolution and partial information, whereas microscopic states correspond to fine resolution and complete information. In this study, we show that coarse-graining in quantum systems can be explained by quantum measurements (POVMs). In quantum systems, the relationship between coarse-grained macroscopic states and entropy is analyzed in the framework of quantum sufficiency and quantum Bayesian theories. To quantify the degree of coarseness, we construct a resource theory of microscopicity and show that it generalizes the resource theory of coherence. Furthermore, given a measurement and a prior distribution for a quantum system, we establish an inferential reference frame as a generalized notion of coherence.