Experimental hierarchy of two-qubit quantum correlations without state tomography.

Area of Science:

• Quantum Information Science
• Quantum Optics
• Quantum Foundations

Background:

• Werner states, a noisy singlet Bell state, exhibit a hierarchy of quantum entanglement, steering, and Bell nonlocality.
• Previous experimental demonstrations relied on full quantum state tomography, requiring extensive measurements (≥15 parameters).

Purpose of the Study:

• To experimentally demonstrate the hierarchy of quantum correlations in Werner states using a reduced measurement set.
• To show that this simplified method can also apply to generalized Werner states.

Main Methods:

• Utilized a novel experimental setup measuring only six elements of a correlation matrix.
• Employed linear combinations of two-qubit Stokes parameters for measurements.

Main Results:

• Successfully demonstrated the hierarchy of quantum entanglement, steering, and Bell nonlocality in Werner states.
• Confirmed the applicability of the method to generalized Werner states.

Conclusions:

• A simplified experimental approach can reveal complex quantum correlation hierarchies.
• This method reduces the experimental overhead for characterizing quantum states and their non-classical properties.