Entanglement of particles versus entanglement of fields: independent quantum resources

TL;DR

This paper clarifies that particle entanglement and field entanglement are distinct quantum phenomena, each observable independently, impacting both fundamental understanding and practical quantum technologies.

Contribution

It rigorously distinguishes particle and field entanglement, providing examples and implications for quantum technology applications.

Findings

Particle and field entanglement are independent phenomena.

Examples demonstrate their separate observability.

Implications for quantum technology harnessing these resources.

Abstract

Nature allows one to explore a manifold of remarkable quantum effects. Most prominently, quantum entanglement can be observed in many-particle systems, between multiple quantized fields, and in hybrid combinations thereof. This diversity, however, also leads to contradicting conclusions about what truly constitutes entanglement in any given physical scenario. By explicitly allowing various perspectives, we rigorously consider different notions of entanglement in the context of first and second quantization. By providing instructive examples, we show that particle entanglement and field entanglement are actually distinct phenomena that can occur and be observed independently of each other. This conclusion not only affects our fundamental understanding but has direct implications for quantum technology which can harness those independent forms of entanglement in practical scenarios.