IBM's simulator allows the use of a reset gate ($|0\rangle$ gate) however when I try to run a circuit using this gate on the hardware it fails to execute. Is there a plan to physically realize this gate?

I am specifically interested in running dissipative algorithms which need to reset the ancilla. I can get around this by invoking extra ancilla to reset my original ancilla - but this requires a lot of qubits for anything but a modest circuit.

It looks like such things are possible, at least in principle: https://arxiv.org/abs/1801.07689


1 Answer 1


I'm afraid that the current interface between the hardware and software does not allow for the reset gate to be performed. Currently the hardware is set up to perform a measurement on qubits simultaneously, and then do nothing else. This means that any operations that come after measurements (either explicitly or as part of operations like reset or if) cannot currently be run on hardware.

As you point out, such operations are indeed possible in principle, and have been done in certain cases in the lab. But making them possible for general use is a more difficult task. It will be done, and that's why the IBM Q Experience and Qiskit allow you to create quantum programs with such operations, but that functionality is not available yet.

  • $\begingroup$ Thanks for the reply! Do you have any sense of how long it would be until such things are available? Weeks, months, years? $\endgroup$
    – bRost03
    Jun 11, 2019 at 14:44
  • 1
    $\begingroup$ Certainly not weeks. It is definitely being worked on, though. $\endgroup$ Jun 12, 2019 at 7:33

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