Exploring the relationship between the faithfulness and entanglement of two qubits

A conceptually simple and experimentally prevalent class of entanglement witnesses, known as fidelity detects via a state's with pure reference state. While existence proofs guarantee that suitable witness can be constructed for every entangled state, such assurances do not apply to witnesses. Recent results have found states cannot detected by witness, unfaithful states, are exceedingly common among bipartite states. In this paper, we show even two-qubit which the simplest all created through application decoherence filtering Bell We also faithfulness is monotonic entanglement, measured concurrence. Finally, verify our predictions using polarization-entangled photons, specifically demonstrate situation in an state brought at expense further reducing