1
$\begingroup$

I am working with a circuit where I use 4 cables, and perform measurements in all of them. Nevertheless, I am only interested in the results from two cables since the other two are ancillas. When I run the circuit in the processor I get more than 4 bars. How do I interpret my results? I attached an example.

Processor:

enter image description here

Simulator:

enter image description here

In this case (and with any other test I ran), if I add up the processor's result for 00000 and 00010 I get almost the same result for 00000 in the simulator. I don't know if this is due to the partial traces.

$\endgroup$
  • $\begingroup$ Also, just to address the "00000" and "00010" probabilities adding up to almost the expected probability, this most likely means that, at the time of running, q[1] had the highest error rate relative to the other qubits. You can see that from the fact that q[1] is coming up as 1 much more often than the other qubits. $\endgroup$ – Matthew Stypulkoski Apr 30 at 13:42
1
$\begingroup$

When you run in the simulator you are running in an "ideal" environment. This means there is no noise that could cause errors in the readouts. That is why the results you get from the simulator are only those 3 expected results.

However, when you run on the real devices, in this case 'ibmqx2', the environment is not a perfect one. The real devices are noisy, and that noise affects the qubits. These errors are seen when you measure the qubits and experience all of the other unexpected results. You will still see the expected answer as having the highest probability in most cases, though.

$\endgroup$
  • $\begingroup$ Then I should just take the values as they're given to me? $\endgroup$ – The Bosco Apr 30 at 13:48
  • $\begingroup$ Essentially yes, the results you receive from the quantum computers should be taken as they are. $\endgroup$ – Matthew Stypulkoski May 1 at 15:12

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.