Mean-field properties of impurity in Bose gas with three-body forces

Orest Hryhorchak, G Panochko, V. Pastukhov

Abstract The detailed mean-field (MF) treatment of the Bose polaron problem in two and three dimensions is presented. Particularly, assuming that impurity is immersed in the dilute Bose gas and interacts with bosons via the hard-sphere two-body potential, we calculate the low-momentum parameters of its spectrum, namely, the binding energy and the effective mass. The limits of applicability of the MF approach to a problem of mobile impurity in Bose–Einstein condensates are discussed by comparing our results to the Monte Carlo simulations data.

Orest Hryhorchak, G. Panochko, V. Pastukhov

G. Panochko, V. Pastukhov

Abstract We exactly calculate the full temperature dependence of Casimir-like forces appearing between two and three static impurities loaded in the ideal Bose gas below the Bose–Einstein condensation transition point. Assuming the short-ranged character of the boson-impurity interaction, the calculation procedure presented here can be easily extended on a Bose system with an arbitrary number of impurities immersed.

A. Nikolaeva, V. Pastukhov

G. Panochko, V. Pastukhov

We exactly calculate the full temperature dependence of the Casimir-like forces appearing between two static impurities loaded in the ideal Bose gas below the Bose-Einstein condensation transition point. Assuming the short-ranged character of the boson-impurity interaction we show how to calculate properties of Bose system with arbitrary number of impurities immersed.

Piotr Wysocki, Ubaldo Cavazos Olivas, Marek Tylutki +1 more

We consider the three-dimensional Bose polaron problem in the regime of finite range interactions and competing length scales. Working in the reference frame of the impurity, we study both static and out of equilibrium properties of the system, in particular the transfer of momentum between the impurity and the host gas. We find that relaxation dynamics can occur via damped oscillations of the impurity velocity with simple dependence on the interaction strength. Furthermore, the equilibration process is sensitive to the type of the impurity-bath interaction. Specifically, interatomic forces describing ion-atom systems lead to much longer timescales and more pronounced oscillations in the strong coupling regime with respect to local interaction potentials. We also find that the effective masses can differ by a large amount between the two scenarios, even if the number of atoms in the polaron cloud remains similar for both cases.