Abstract
The quantum state of a superconducting transmon qubit inside a three-dimensional cavity is monitored by transmission of a microwave field through the cavity. The information inferred from the measurement record is incorporated in a density matrix , which is conditioned on probe results until , and in an auxiliary matrix , which is conditioned on probe results obtained after . Here, we obtain these matrices from experimental data and we illustrate their application to predict and retrodict the outcome of weak and strong qubit measurements.
- Received 1 September 2014
DOI:https://doi.org/10.1103/PhysRevLett.114.090403
© 2015 American Physical Society
Synopsis
Predicting the Quantum Past
Published 5 March 2015
Predictions for a quantum measurement are improved by probing the system after the measurement and evolving a model backward in time.
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