Quantum Generalized Subsystems

TL;DR

This paper introduces a new formalism for quantum subsystems using completely positive maps and correlation functions, enabling unified descriptions, composition, and the concept of generalized entanglement across various quantum models.

Contribution

It presents a novel formalism that unifies existing and new methods for quantum system reduction, incorporating generalized entanglement and applicable to diverse quantum models.

Findings

Unified framework for quantum subsystems using completely positive maps.

Application to fermionic, bosonic, and SU(2) symmetric systems.

Demonstrates the composition and generalized entanglement within the formalism.

Abstract

We propose a new formalism of quantum subsystems which allows to unify the existing and new methods of reduced description of quantum systems. The main mathematical ingredients are completely positive maps and correlation functions. In this formalism generalized quantum systems can be composed and there is a notion of generalized entanglement. Models of fermionic and bosonic systems and also quantum systems described by the SU(2) symmetry are studied.