Correcting for the expected with readout correction

Now that we have some knowledge about what might go wrong when we use our qubits for quantum calculations, is there anything that we can do about it? There are essentially two approaches here, at least for the small quantum backends that we have at our disposal.

First, we can make sure that the quantum programs that we run have a fighting chance of completing before the qubits get lost due to decoherence, the T1 and T2 times that we explored. This means that we make the programs short.

Second, we can take a good look at various readout errors and see if we can mitigate those. If you remember in Chapter 7, Simulating Quantum Computers with Aer, we could pull in actual backend qubit data to qasm_simulator and have it behave like an NISQ backend. We can do the same in reverse, analyze the measurement errors for a backend, and use that data to create a mitigation map to counteract erroneous measurements.

Getting ready

The...