High-Fidelity Qubit Readouts: Definition & Overview

[Raptor112]

What does one mean when one says "high-fidelity qubit readouts"?

 

[Strilanc]

What does one mean when one says "high-fidelity qubit readouts"?

That the process/instrument measuring a qubit usually returns the right result, instead of returning a wrong result or losing the result.

 

[Raptor112]

That the process/instrument measuring a qubit usually returns the right result, instead of returning a wrong result or losing the result.

So here the right results means the state the qubit is prepared in before the measurement takes place?

 

[Strilanc]

Yes, keeping in mind that some results are going to be unavoidably probabilistic (in which case we want the measurement probabilities to closely match the theoretical predictions). Also we want to see correct correlations when doing combined measurements of multiple entangled qubits, and that becomes exponentially hard if you only think in terms of measuring single qubits accurately instead of in terms of a quantum error correcting code for the whole state.

 

[f95toli]

So here the right results means the state the qubit is prepared in before the measurement takes place?

Indeed, it is mainly a "technical" term that says something about how good your measurement method/setup is . High fidelity means you will nearly always get the "right" result and that your equipment won't give you erroneous reading because of noise, timing issues etc.