Exploring the boundary of quantum correlations with a time-domain optical processor.

Area of Science:

• Quantum Information Science
• Quantum Foundations
• Quantum Optics

Background:

• Contextuality is a fundamental quantum mechanical principle, distinguishing it from classical physics.
• Greenberger-Horne-Zeilinger (GHZ)-type paradoxes are key proofs of quantum contextuality, highlighting its incompatibility with noncontextual hidden-variable theories.
• Identifying GHZ paradoxes with minimal contextual involvement and maximal nonclassicality is an ongoing challenge.

Purpose of the Study:

• To derive a novel Greenberger-Horne-Zeilinger (GHZ)-type paradox.
• To achieve the theoretical lower bound for context-cover number in quantum contextuality proofs.
• To experimentally demonstrate this paradox in a high-dimensional quantum system.

Main Methods:

• Derivation of a GHZ-type paradox with a context-cover number of 3.
• Experimental implementation using a time-domain fiber optical platform.
• Utilizing high-speed modulation, convolution, and homodyne detection in a 37-dimensional Hilbert space with time-multiplexed pulsed coherent light.

Main Results:

• Successfully derived a GHZ-type paradox saturating the lower bound of context-cover number 3.
• Experimental verification of the quantum prediction in a 37-dimensional setup.
• Demonstrated a strong form of contextuality in high-dimensional Hilbert space.

Conclusions:

• The derived GHZ-type paradox represents the most contextually minimal proof of quantum contextuality to date.
• The experimental demonstration validates the theoretical findings and showcases the potential of high-dimensional optical systems.
• This work opens new avenues for exploring complex quantum correlations using time-multiplexed optical platforms.