How is it possible to return quantum state vector from real quantum device? For example, i designed a quantum circuit as a function and the return of function was a vector (qml.state()). I can return the state with simulator. But with quantum computer, i got this error:
QuantumFunctionError: The current device is not capable of returning the state.
Hey @sassan_moradi! Unfortunately, the answer to your question is no; a real quantum device cannot return the quantum state that describes itself. There is an entire field of quantum information / computing dedicated to reconstructing quantum states from data that we can obtain from a quantum device: quantum state tomography.