State and Measurement Tomography of an Exchange-Only Spin Qubit

Published

September 1, 2013

Author(s)

Jacob M. Taylor, Medford Jim, Johannes Beil, Stephen Bartlett, Andrew Doherty, Emmanuel Rashba, David P. DiVincenzo, H Lu, A. C. Gossard

Abstract

We demonstrate the initialization, full electrical control, and state tomography of an exchange- only spin qubit in a GaAs heterostructure. Decoherence and leakage from the qubit subspace are accounted for with a model of charge noise and fluctuating Overhauser fields. The linear triple quantum dot structure allows for the initialization of multiple high-fidelity input states, which are used with a Maximum Likelihood Estimation (MLE) technique to systematically characterize the generalized measurements in a demonstration of measurement tomography. This technique resulted in an average measurement fidelity of 75% and an average visibility of 49%.

Citation

Nature Nanotechnology

Pub Type

Journals

Download Paper

https://doi.org/10.1038/nnano.2013.168

Keywords

Quantum dots, quantum computing

Citation

Taylor, J. , Jim, M. , Beil, J. , Bartlett, S. , Doherty, A. , Rashba, E. , DiVincenzo, D. , Lu, H. and Gossard, A. (2013), State and Measurement Tomography of an Exchange-Only Spin Qubit, Nature Nanotechnology, [online], https://doi.org/10.1038/nnano.2013.168 (Accessed October 11, 2025)