Quantum logic gate

{wiki}

= Quantum gate
{synonym}

At <quantum computing is just matrix multiplication>{full} we saw that making a quantum circuit actually comes down to designing one big <unitary matrix>.

We have to say though that that was a bit of a lie.

Quantum programmers normally don't just produce those big matrices manually from scratch.

Instead, they use </quantum logic gates>.

The following are the main reasons for that:
* <quantum logic gates are needed because you can't compute the matrix explicitly as it grows exponentially>{full}
* <quantum logic gates are needed for physical implementation>{full}
