Southwest Quantum Information and Technology

Reducing ion measurement errors with Bayesian techniques

Presenting Author: Shawn Geller, National Institute of Standards and Technology, Boulder
Contributing Author(s): Scott Glancy, Dietrich Liebfried, Emanuel Knill

We describe a measurement protocol for trapped ions using repeated measurements. By employing the non-demolition nature of measurement of a fluorescence-based qubit, we can make repeated measurements to extract more information out of the system. Ideally, one would perform a long measurement where we can collect many photons, and then perform a hypothesis test to determine the state of the ion. However, there are spurious depumping and repumping effects that take the qubit into and out of the many other states in the hyperfine manifold during measurement. By using a Hidden Markov Model, we can efficiently estimate the probability that there was an unwanted state transition during measurement. We furthermore leverage the microwave control of the qubit to induce state transitions that will minimize the probability of error, which we calculate using Bayesian techniques.

(Session 5 : Saturday from 5:00pm - 7:00pm)