Bound entangled ststes of four qubits in tomographic probability representation

TL;DR

This paper analyzes the bound entangled Smolin state of four qubits using tomographic probability representation and introduces a qubit portrait method to demonstrate entanglement through Bell inequality violation.

Contribution

It provides an explicit spin tomogram of the four-qubit bound entangled state and applies a novel qubit portrait method to verify entanglement via Bell inequality violation.

Findings

Explicit spin tomogram of the four-qubit bound entangled state is derived.

Qubit portrait method successfully demonstrates Bell inequality violation.

Confirms the entanglement property of the Smolin state using tomographic and Bell analysis.

Abstract

The entanglement phenomenon on example of Smolin state of four qubits is discussed. This state is known as bound entangled state and the spin tomogram of the state is found in explicit form. The qubit portrait method is used the Bell inequality violation which provides another tool to prove the property of entanglement of the four-qubit state under consideration.