Precisely how precise can we get?
In my recent article titled “Quantum Phase Estimation!” I showed how Fire Opal can illuminate useful results from within the noise of a 6-qubit QPE circuit. In response, Jack Krupansky asked how precise we can get. That’s a great question, so let’s find out, shall we?
But, first, a brief review:
6-Qubit QPE with 5 Counting Qubits
TL;DR: the measurement results gives us the information we need to estimate the phase. But, if we can add more counting qubits, we can improve the accuracy of our estimation.
Circuit depth: 211
CNOT count: 163
Our Smallest Circuit
A reminder: the smallest circuit we’re testing here looks like this on real hardware. Look at all that depth. Look at all those error-loving multi-qubit operations. I had to take a screenshot of it because Medium would not allow me to upload the original full-sized image of the circuit. So, when we’re testing a 16-qubit QPE with 15 counting qubits, keep in mind how barely-readable the circuit is…
