Self-Consistent Quantum Process Tomography

By Seth T. Merkel, Jay M. Gambetta, John A. Smolin, S. Poletto, A. C'orcoles, Blake R. Johnson, C. Ryan, Matthias Steffen. 2012

277 citations recorded by the source corpus.

Quantum process tomography is a necessary tool for verifying quantum gates and diagnosing faults in architectures and gate design. We show that the standard approach of process tomography is grossly inaccurate in the case where the states and measurement operators used to interrogate the system are generated by gates that have some systematic error, a situation all but unavoidable in any practical setting. These errors in tomography can not be fully corrected through oversampling or by performing a larger set of experiments. We present an alternative method for tomography to reconstruct an entire library of gates in a self-consistent manner. The essential ingredient is to dene a likelihood function that assumes nothing about the gates used for preparation and measurement. In order to make the resulting optimization tractable we linearize about the target, a reasonable approximation when benchmarking a quantum computer as opposed to probing a black-box function.

Subfields: Artificial Intelligence, Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/598555b20fc589bf7ddeaeb698b0d85e0da43d86

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Artificial Intelligence

In Electrical and Electronic Engineering

Citations in the corpus

The randomized measurement toolbox (2022, background): “GST grew out of the need for self-consistent estimates of a quantum process together with the noisy measurements and state preparations used as probes 105 .”
Quantum-enhanced measurements without entanglement (2017, background): “Estimations with dissipative dynamics (Alipour et al., 2014; Bellomo et al., 2009, 2010a,b; Zhang and Sarovar, 2015) are also instances of process tomography (Baldwin et al., 2014; Bendersky and Paz, 2013; Merkel et al., 2013; Mohseni et al., 2008) with partial prior knowledge.”
Demonstration of quantum volume 64 on a superconducting quantum computing system (2020, background): “randomized benchmarking [43, 44] and gate set tomography [45, 46], QV was developed as a holistic system measure and hence is sensitive to SPAM-errors.”
Practical Quantum Error Mitigation for Near-Future Applications (2017, methodology): “[15,16] (also see Appendix E), the estimation of an operation and the actual”
Demonstration of qubit operations below a rigorous fault tolerance threshold with gate set tomography (2016, methodology): “GST protocols based on short quantum circuits were developed at IBM [39] and Sandia [32].”