Nonlocality and entanglement in the XY model

TL;DR

This paper investigates the relationship between nonlocality and entanglement in the XY model, revealing new insights into their distinctions and implications for quantum information tasks in many-body systems.

Contribution

It provides a detailed analysis of nonlocality and entanglement in the XY model, highlighting their differences and potential limitations for quantum information processing.

Findings

Nonlocality is characterized by Bell inequality violations.

Entanglement and nonlocality are distinct in the XY model.

Results suggest limitations for entanglement in quantum information tasks.

Abstract

Nonlocality and quantum entanglement constitute two special features of quantum systems of paramount importance in quantum information theory (QIT). Essentially regarded as identical or equivalent for many years, they constitute different concepts. Describing nonlocality by means of the maximal violation of two Bell inequalities, we study both entanglement and nonlocality for two and three spins in the XY model. Our results shed a new light into the description of nonlocality and the possible information-theoretic task limitations of entanglement in an infinite quantum system.