In Exercise V.2.3., may be there is an error of |ψ>=(0,1/√2,-1/√2,0)T? It should be (0,-1/√2,1/√2,0)T indead. Please check, I try to calculate the result of the circuit in the encloser.
Hi @jsgs8skwkw , welcome to the Forum!
I think you might be right. Both of these states are eigenstates corresponding to the -2 eigenvalue, but the circuit is actually implementing [0,\frac{-1}{\sqrt2},\frac{1}{\sqrt2},0]^T.
We will work on fixing this. Thank you for pointing it out!