Universal measure of entanglement

Area of Science:

• Quantum Information Theory
• Quantum Many-Body Systems

Background:

• Distinguishing classical and quantum correlations is crucial for understanding complex quantum systems.
• Existing measures of entanglement are often difficult to compute for multipartite systems.

Purpose of the Study:

• Develop a general framework for separating classical and quantum correlations in multipartite systems.
• Define a computable measure of multipartite entanglement for pure states.

Main Methods:

• Developed a general framework for correlation separation.
• Generalized the Schmidt decomposition for multipartite pure states.
• Defined entanglement as the difference between quantum and separable state correlations.

Main Results:

• Introduced a novel measure generalizing entanglement of formation to multipartite systems.
• This measure provides an upper bound for the relative entropy of entanglement.
• Successfully applied and analyzed the framework for pure three-qubit states.

Conclusions:

• The developed framework provides a robust method for quantifying multipartite entanglement.
• The new measure is directly computable for pure states, simplifying analysis.
• A classification of three-qubit states based on minimal decompositions was established.