AerState::probability does not work as expected with the stabilizer simulator

[aromanro]

Informations

• Qiskit Aer version: Latest development version
• Python version: Irrelevant, as it's called from C++
• Operating system: Windows, linux, macos

What is the current behavior?

Calling AerState::probability throws an exception with the message "Save amplitude square must be defined on full width of qubits." The exception comes from here: https://github.com/Qiskit/qiskit-aer/blob/269c26fd0552836db54f27d511e07167f58d7990/src/simulators/stabilizer/stabilizer_state.hpp#L578

Steps to reproduce the problem

Configure a stabilizer simulator then call 'probability' for an outcome.

What is the expected behavior?

Return the probability.

Suggested solutions

Modify AerState::probability to add the list of qubits, that is, insert

  for (uint_t i = 0; i < num_of_qubits_; ++i)
    op.qubits.push_back(i);

somewhere here: https://github.com/Qiskit/qiskit-aer/blob/269c26fd0552836db54f27d511e07167f58d7990/src/controllers/state_controller.hpp#L1382

This issue is similar with this one: https://github.com/Qiskit/qiskit-aer/issues/2234