Function chsh_correlation 

pub fn chsh_correlation(
    state: &TwoQubitState,
    a1: f64,
    a2: f64,
    b1: f64,
    b2: f64,
) -> f64

CHSH correlation: S = E(a1,b1) - E(a1,b2) + E(a2,b1) + E(a2,b2). Each angle specifies a measurement axis in the XZ plane. Returns |S|, which violates Bell inequality when > 2.