a)
twhittle 21 Dec 2013 03:59
$\frac{1}{\sqrt2}(|+\rangle|+\rangle+|-\rangle|-\rangle) =$
$\frac{1}{\sqrt2}\left(\frac{1}{2}\left(|0\rangle+|1\rangle\right)\otimes\left(|0\rangle+|1\rangle\right)+\frac{1}{2}\left(|0\rangle-|1\rangle\right)\otimes\left(|0\rangle-|1\rangle\right)\right)=$
$\frac{1}{2\sqrt2}\left(|0\rangle|0\rangle + |0\rangle|1\rangle + |1\rangle|0\rangle + |1\rangle|1\rangle + |0\rangle|0\rangle - |0\rangle|1\rangle - |1\rangle|0\rangle + |1\rangle|1\rangle\right)=$
$\frac{1}{\sqrt2}(|0\rangle|0\rangle+|1\rangle|1\rangle)$