Information gain and loss for a quantum Maxwell's demon

Naghiloo, M. and Alonso, J. J. and Romito, A. and Lutz, E. and Murch, K. W. (2018) Information gain and loss for a quantum Maxwell's demon. Physical review letters, 121 (3): 030604. ISSN 1079-7114

[thumbnail of 1802.07205v1]
PDF (1802.07205v1)
1802.07205v1.pdf - Accepted Version
Available under License Creative Commons Attribution-NonCommercial.

Download (5MB)


We use continuous weak measurements of a driven superconducting qubit to experimentally study the information dynamics of a quantum Maxwell's demon. We show how information gained by a demon who can track single quantum trajectories of the qubit can be converted into work using quantum coherent feedback. We verify the validity of a quantum fluctuation theorem with feedback by utilizing information obtained along single trajectories. We demonstrate, in particular, that quantum backaction can lead to a loss of information in imperfect measurements. We furthermore probe the transition between information gain and loss by varying the initial purity of the qubit.

Item Type:
Journal Article
Journal or Publication Title:
Physical review letters
Additional Information:
© 2018 American Physical Society
Uncontrolled Keywords:
?? quant-phcond-mat.mes-hallcond-mat.stat-mechphysics and astronomy(all)discipline-based research ??
ID Code:
Deposited By:
Deposited On:
28 Aug 2018 10:00
Last Modified:
31 Dec 2023 00:59