I am familiar with logic gates which are in classical computers. They are made up of semiconductor devices like diodes and transistors.

There are some companies which are working on the universal quantum computers such as Google, IBM, Honeywell.

How does quantum logic gates such as Pauli-X,Y,Z, Hadamard, CNOT, CCNOT look like in the circuits of those universal quantum computers? I have referred to many white papers, but in all of them I saw them representing these gates as matrices.

Are Quantum logic gates even physically realized yet OR are they only theoretically proved using matrices?

Can you please attach some real picture of these processors, and point out the quantum logic gates?

  • 1
    $\begingroup$ Yes, quantum gates have been already implemented. Look at IBM's or Google's quantum computers, they already work, although at a small scale and with relatively high decoherence. This might be helpful. $\endgroup$
    – epelaez
    Commented Jun 30, 2021 at 23:12
  • $\begingroup$ Possible duplicate: quantumcomputing.stackexchange.com/questions/9609/… $\endgroup$ Commented Jul 1, 2021 at 0:23
  • $\begingroup$ What does "OdI" mean? $\endgroup$
    – M. Stern
    Commented Jul 1, 2021 at 6:09
  • $\begingroup$ there is no need to mark "EDITs" as such. Revision history of all posts is available, so you can just edit posts in such a way that someone reading the last version for the first time won't have to reconstruct its whole history $\endgroup$
    – glS
    Commented Jul 1, 2021 at 8:35

1 Answer 1


The quantum gates in a superconducting qubit chip are not devices located in space made out of metal. They are processes applied over time. They look like carefully choreographed microwave chirps travelling down wires attached to the superconducting loops that are the qubits.

Instead of moving the data through the operations, you move the operations through the data.

enter image description here

Figure is from https://arxiv.org/abs/1709.06678

  • $\begingroup$ Is this process for ion-trapped quantum chips? Is ion-trapped quantum computing an architecture for a universal quantum computer? If not, Do universal quantum computers follow the same process? > Can you please explain a little bit more on this? "Instead of moving the data through the operations, you move the operations through the data." $\endgroup$
    – Vishnu
    Commented Jun 30, 2021 at 23:44
  • $\begingroup$ @Vishnu Ion traps use laser pulses instead of microwave pulses. Photonic QC sometimes involve gates placed into space that the qubits fly through, in the way you are picturing, but other times they also use time varying control signals. It's complicated; there's not just one way to do it. $\endgroup$ Commented Jun 30, 2021 at 23:44

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