• DOI:10.1103/PhysRevLett.122.030403
• Corpus ID: 51693379

Using Polarons for sub-nK Quantum Nondemolition Thermometry in a Bose-Einstein Condensate.

@article{Mehboudi2019UsingPF,
  title={Using Polarons for sub-nK Quantum Nondemolition Thermometry in a Bose-Einstein Condensate.},
  author={Mohammad Mehboudi and Aniello Lampo and Christos Charalambous and Luis A. Correa and Miguel Angel Garcia-March and Maciej Lewenstein},
  journal={Physical review letters},
  year={2019},
  volume={122 3},
  pages={
          030403
        }
}

• M. Mehboudi, A. Lampo, +3 authors M. Lewenstein
• Published 19 June 2018
• Physics
• Physical review letters

We introduce a novel minimally disturbing method for sub-nK thermometry in a Bose-Einstein condensate (BEC). Our technique is based on the Bose polaron model; namely, an impurity embedded in the BEC acts as the thermometer. We propose to detect temperature fluctuations from measurements of the position and momentum of the impurity. Crucially, these cause minimal backaction on the BEC and hence, realize a nondemolition temperature measurement. Following the paradigm of the emerging field of quantum thermometry, we combine tools from quantum parameter estimation and the theory of open quantum systems to solve the problem in full generality. We thus avoid any simplification, such as demanding thermalization of the impurity atoms, or imposing weak dissipative interactions with the BEC. Our method is illustrated with realistic experimental parameters common in many labs, thus showing that it can compete with state-of-the-art destructive techniques, even when the estimates are built from the outcomes of accessible (suboptimal) quadrature measurements.