Swap test

[andrewmusselman]

Swap test is a common method for measuring the overlap between two quantum states, requiring additional qubits and controlled-SWAP (Fredkin) gates.

[shashikant-op]

if this issue is still open then can i work on it

[rawkintrevo]

Yes, I had it assigned to me to remember to do something with it, and then got distracted with FOSDEM (then some personal stuff immediately following that). I've done nothing of note on it. @shashikant-op if you want to take it go ahead.

[andrewmusselman]

@shashikant-op go for it, thanks for volunteering!