Level 3
An entangled joint state cannot be written as a mixture of product states. The ideal Bell example has correlated computational-basis outcomes, each individually random.
A Bell pair mostly returns matching results: 00 or 11.
H creates uncertainty; CNOT links the second qubit to the first.
Entanglement powers teleportation, error correction, and many algorithmic speedups.
Entanglement does not let you send faster-than-light messages.
Run Bell and inspect the 00/11 correlations. Those counts alone are not a general entanglement witness.
# Bell qubits 2 H 0 CX 0 1 MEASURE 0 MEASURE 1
In the Bell sample, which outputs should dominate?