A Caltech Library Service

Weak Measurement of a Superconducting Qubit Reconciles Incompatible Operators

Monroe, Jonathan T. and Yunger Halpern, Nicole and Lee, Taeho and Murch, Kater W. (2021) Weak Measurement of a Superconducting Qubit Reconciles Incompatible Operators. Physical Review Letters, 126 (10). Art. No. 100403. ISSN 0031-9007. doi:10.1103/physrevlett.126.100403.

[img] PDF - Published Version
See Usage Policy.

[img] PDF - Submitted Version
See Usage Policy.

[img] PDF (experimental details and backup calculations) - Supplemental Material
See Usage Policy.


Use this Persistent URL to link to this item:


Traditional uncertainty relations dictate a minimal amount of noise in incompatible projective quantum measurements. However, not all measurements are projective. Weak measurements are minimally invasive methods for obtaining partial state information without projection. Recently, weak measurements were shown to obey an uncertainty relation cast in terms of entropies. We experimentally test this entropic uncertainty relation with strong and weak measurements of a superconducting transmon qubit. A weak measurement, we find, can reconcile two strong measurements’ incompatibility, via backaction on the state. Mathematically, a weak value—a preselected and postselected expectation value—lowers the uncertainty bound. Hence we provide experimental support for the physical interpretation of the weak value as a determinant of a weak measurement’s ability to reconcile incompatible operations.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Monroe, Jonathan T.0000-0001-8629-7797
Yunger Halpern, Nicole0000-0001-8670-6212
Lee, Taeho0000-0003-4883-4744
Murch, Kater W.0000-0002-1536-294X
Additional Information:© 2021 American Physical Society. Received 25 August 2020; revised 19 November 2020; accepted 29 January 2021; published 11 March 2021. K. W. M. acknowledges support from NSF Grant No. PHY-1752844 (CAREER) and use of facilities at the Institute of Materials Science and Engineering at Washington University. N. Y. H. is grateful for funding from the Institute for Quantum Information and Matter, an NSF Physics Frontiers Center (NSF Grant No. PHY-1125565) with support of the Gordon and Betty Moore Foundation (GBMF-2644), and for a NSF grant for the Institute for Theoretical Atomic, Molecular, and Optical Physics at Harvard University and the Smithsonian Astrophysical Observatory. This project began at the KITP’s “Quantum Thermodynamics" conference and so was supported in part by the National Science Foundation under Grant No. NSF PHY-1748958.
Group:Institute for Quantum Information and Matter
Funding AgencyGrant Number
Institute for Quantum Information and Matter (IQIM)UNSPECIFIED
Gordon and Betty Moore FoundationGBMF-2644
Issue or Number:10
Record Number:CaltechAUTHORS:20210312-141741101
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:108416
Deposited By: Tony Diaz
Deposited On:12 Mar 2021 22:34
Last Modified:16 Nov 2021 19:11

Repository Staff Only: item control page