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  • 1802.07205v1

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Information gain and loss for a quantum Maxwell's demon

Research output: Contribution to Journal/MagazineJournal articlepeer-review

  • M. Naghiloo
  • J. J. Alonso
  • A. Romito
  • E. Lutz
  • K. W. Murch
Article number030604
<mark>Journal publication date</mark>17/07/2018
<mark>Journal</mark>Physical review letters
Issue number3
Number of pages6
Publication StatusPublished
<mark>Original language</mark>English


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.

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© 2018 American Physical Society