Preserving Entanglement During Weak Measurement Demonstrated with a Violation of the Bell–Leggett–Garg inequality

Authors

T. C. White, University of California, Santa Barbara
J. Y. Mutus, University of California, Santa Barbara
Justin Dressel, Chapman UniversityFollow
J. Kelly, University of California, Santa Barbara
R. Barends, University of California, Santa Barbara
E. Jeffrey, University of California, Santa Barbara
D. Sank, University of California, Santa Barbara
A. Megrant, University of California, Santa Barbara
B. Campbell, University of California, Santa Barbara
Yu Chen, University of California, Santa Barbara
Z. Chen, University of California, Santa Barbara
B. Chiaro, University of California, Santa Barbara
A. Dunsworth, University of California, Santa Barbara
I.-C. Hoi, University of California, Santa Barbara
C. Neill, University of California, Santa Barbara
P. J. J. O'Malley, University of California, Santa Barbara
P. Roushan, University of California, Santa Barbara
A. Vainsencher, University of California, Santa Barbara
J. Wenner, University of California, Santa Barbara
A. N. Korotkov, University of California, Riverside
John M. Martinis, University of California, Santa Barbara

Document Type

Article

Publication Date

2-16-2016

Abstract

Weak measurement has provided new insight into the nature of quantum measurement, by demonstrating the ability to extract average state information without fully projecting the system. For single-qubit measurements, this partial projection has been demonstrated with violations of the Leggett–Garg inequality. Here we investigate the effects of weak measurement on a maximally entangled Bell state through application of the Hybrid Bell–Leggett–Garg inequality (BLGI) on a linear chain of four transmon qubits. By correlating the results of weak ancilla measurements with subsequent projective readout, we achieve a violation of the BLGI with 27 s.d.s. of certainty.

Comments

This article was originally published in npj Quantum Information, volume 2, in 2016. DOI: 10.1038/npjqi.2015.22

Recommended Citation

White, T. C. et al. Preserving entanglement during weak measurement demonstrated with a violation of the Bell–Leggett–Garg inequality. NPJ Quantum Information 2, 15022 (2016). doi: 10.1038/npjqi.2015.22

Peer Reviewed

1

Copyright

University of New South Wales/Macmillan Publishers Limited

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 License.