Spin singlet state
= Spin singlet state
{title2=$|\Psi^-\rangle$}
{wiki=Singlet_state}
The two-spin singlet is
$$
|\Psi^-\rangle=\frac{|01\rangle-|10\rangle}{\sqrt2}.
$$
Spin measurements along axes $\mathbf a$ and $\mathbf b$ have correlation $E(\mathbf a,\mathbf b)=-\mathbf a\cdot\mathbf b$, and equal axes give perfect anticorrelation.