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Entanglement-based QKD
Entangled-pair correlations support key generation and Bell-style disturbance checks under idealized assumptions.
Alice and Bob measure entangled pairs in selected bases; nonclassical correlations can reveal disturbance.
The interactive demo uses a simplified CHSH-style score S from four correlation settings; |S| > 2 is a Bell-violation indicator.
CHSH S proxy
2.606
Bell indicator
above 2
This is a teaching proxy for correlation visibility, not a loophole-free device-independent security test.
This E91 worksheet keeps the Bell-style lesson short, explicit, and exportable without overstating the security claim.
CHSH S proxy
2.606
Bell margin
0.606
Indicator
above 2
Step 1
Adjust visibility and noise, then observe how the CHSH-style score changes.
Step 2
Check whether the score stays above the classical threshold of 2.
Step 3
Explain what a reduced Bell margin means for correlation quality and lab confidence.
Bell-style interpretation
The current CHSH-style score is 2.606, which is above 2 the classical threshold of 2. The margin is 0.606.
This Bell-style worksheet is instructional only. It should not be read as a loophole-free E91 or device-independent security claim.
Record what changed in the Bell indicator and export the answers for teaching-lab review.
Question 1
Does the current setting stay above the classical CHSH threshold, and what does that imply in this teaching model?
Expected observation: The current score is 2.606, which is above 2; that indicates whether the simplified lesson still shows Bell-style nonclassical correlation.
Question 2
How do visibility loss and added noise move the Bell indicator?
Expected observation: Both lower visibility and higher noise shrink the CHSH score, reducing or removing the Bell-violation margin.
Question 3
Why is the Bell indicator here not a device-independent security proof?
Expected observation: The lab compresses sampling, detection efficiency, timing, memory effects, and loophole closure into two scalar sliders, so it is only a correlation-intuition worksheet.