Interpreting the macroscopic pointer by analyzing the Einstein-Podolsky-Rosen steering of an entangled macroscopic superposition state

TL;DR

This paper investigates EPR steering in macroscopic superposition states, revealing that large cat-systems can appear classically mixed despite entanglement, and proposes experimental signatures for this phenomenon.

Contribution

It demonstrates that EPR steering can serve as a signature of Schrödinger cat paradoxes in macroscopic systems and offers a hybrid quantum-classical interpretation of measurement pointers.

Findings

Large cat-systems can be modeled as classical mixtures despite entanglement.

Two experimental signatures of EPR steering in macroscopic superpositions are proposed.

Many Schrödinger cat paradoxes can be explained through microscopic nonlocality.

Abstract

We examine Einstein-Podolsky-Rosen's (EPR) steering nonlocality for two realisable Schrodinger cat-type states where a meso/ macroscopic system (called the "cat"-system) is entangled with a spin-$1/2$ system. For large cat-systems, we show that a local hidden state model is near-satisfied, meaning that the cat-system can be consistent with being in a mixture of "dead" and "alive" states despite that it is entangled with the spin system. We justify that a rigorous signature of the Schrodinger cat-type paradox is the EPR-steering of the cat-system and provide two experimental signatures. This leads to a hybrid quantum/ classical interpretation of the macroscopic pointer of a measurement device and suggests many Schrodinger cat-type paradoxes can be explained by microscopic nonlocality.