Quantum adder mod 4

Question

Does anyone has (or is aware of) a solution to Nielsen's QCQI 4.36 exercise: construct a circuit to add two-qubit numbers x and y modulo 4 vs $|x,y\rangle \rightarrow |x, x+y \mod 4\rangle$

Welcome to Quantum Computing SE! Would you be able to [edit] the question to include details of what you've tried and where exactly you're having problems? — Mithrandir24601, Dec 21 '19 at 11:02
Possible duplicate of Constructing a circuit which performs the transformation $|x,y\rangle \to |x, x + y \bmod 4\rangle$ — Sanchayan Dutta, Dec 21 '19 at 18:20
Thank you for your comments. Two notes here: 1. I consider the question is clearly formulated ! AND 2. Yes, it's a duplicate of the mentioned post (sorry for this omission) — moldos, Dec 22 '19 at 06:54

score 3 · Answer 1 · answered Dec 19 '19 at 13:10

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The trick is to break down, bit by bit, what the calculation is that you need. You'll see on the right-hand side of the circuit, I've stated what the outcomes need to be. Hopefully, you also recognise some of those outputs (particularly the top qubit), so that rapidly starts to formulate the circuit...

answered Dec 19 '19 at 13:10

DaftWullie

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Crystal clear. Thank you. – moldos Dec 22 '19 at 06:52

Quantum adder mod 4

1 Answers1