Classical simulation of partially entangled states

TL;DR

This paper explores classical simulation of partially entangled two-qubit states, demonstrating that isotropic states can be simulated classically while pure states and their mixtures cannot, highlighting limits of separability as a quantum indicator.

Contribution

It shows that all partially entangled isotropic states are classically simulatable, but pure states and mixtures are not, revealing the nuanced relationship between separability and quantum nature.

Findings

All partially entangled isotropic states can be simulated classically.

Pure partially entangled states and their mixtures cannot be simulated classically.

Separability does not universally determine a state's quantum nature.

Abstract

We investigate the possibility of simulating partially entangled two qubit states by separable states of higher spins. First, we show that all partially entangled isotropic states can be simulated classically. We further investigate partially entangled pure states, and their binary mixtures and find that these systems forbid such a simulation, signifying that separability does not have a universal character in determining the inherent quantum nature of a state.