Distillation protocols: output entanglement and local mutual information

Area of Science:

• Quantum Information Science
• Quantum Entanglement
• Information Theory

Background:

• Bipartite quantum states are fundamental in quantum information.
• Entanglement distillation aims to increase entanglement quality from noisy states.
• Local mutual information quantifies classical correlations.

Purpose of the Study:

• To derive a relationship between local mutual information and average output entanglement.
• To establish bounds on entanglement yield in distillation protocols.
• To investigate the saturation of these bounds.

Main Methods:

• Derivation of a complementary behavior for arbitrary bipartite ensembles.
• Analysis of entanglement distillation protocols involving state discrimination.
• Application to Bell-diagonal states.

Main Results:

• A complementary relationship between local mutual information and average output entanglement is established.
• New bounds on the yield of entanglement in distillation protocols are derived.
• The derived bound is shown to be saturated for Bell-diagonal states in the hashing protocol.

Conclusions:

• The findings provide fundamental insights into the interplay of classical and quantum correlations.
• The derived bounds offer practical implications for optimizing quantum entanglement distillation.
• The saturation of the bound highlights the efficiency of specific protocols for certain quantum states.