Open quantum systems approach to Bose polaron problems with applications*

We discuss the dynamics of one and two quantum impurities immersed in a homogeneous or trapped Bose-Einstein condensate (BEC) in the framework of the quantum Brownian motion model [1-4]. When the impurities are untrapped, we show that the long-time behavior is superdiffusive. For the trapped impurities, we discuss the realistic conditions for the final state to be squeezed or to present entanglement in the two impurities case. We discuss two applications: i) for quantum non-demolition thermometry in a BEC [5]; and ii) to construct a system that permits a heat current between two BECs, and evaluate this system as a thermal diode [6].
[1] A. Lampo et al., Quantum 1, 30 (2017).
[2] A. Lampo et al. Quantum Brownian Motion Revisited (Springer, 2019).
[3] A. Lampo et al. Phys. Rev. A 98 063630 (2018).
[4] C. Charalambous et al. SciPost 6 10 (2019).
[5] M. Mehboudi et al. Phys. Rev. Lett. 122, 030403 (2019).
[6] C. Charalambous et al. Arxiv:1905.02016.