Ex5 10

$\def\abs#1{|#1|}\def\i{\mathbf {i}}\def\ket#1{|{#1}\rangle}\def\bra#1{\langle{#1}|}\def\braket#1#2{\langle{#1}|{#2}\rangle}\def\tr{\mathord{\mbox{tr}}}\mathbf{Exercise\ 5.10}$

An $n$-qubit cat state is the state $\frac{1}{\sqrt 2}(\ket{00\dots 0} + \ket{11\dots 1}$. Design a circuit which, upon input of $\ket{00\dots 0}$, constructs a cat state.