Projects per year
We consider an impurity immersed in a Bose-Einstein condensate with tunable boson-impurity interactions. Such a Bose polaron has recently been predicted to exhibit an intriguing energy spectrum at finite temperature, where the ground-state quasiparticle evenly splits into two branches as the temperature is increased from zero [Guenther, Phys. Rev. Lett. 120, 050405 (2018)PRLTAO0031-900710.1103/PhysRevLett.120.050405]. To investigate this theoretical prediction, we employ a recently developed variational approach that systematically includes multibody correlations between the impurity and the finite-temperature medium, thus allowing us to go beyond previous finite-temperature methods. Crucially, we find that the number of quasiparticle branches is simply set by the number of hole excitations of the thermal cloud, such that including up to one hole yields one splitting, two holes yields two splittings, and so on. Moreover, this effect is independent of the impurity mass. We thus expect that the exact ground-state quasiparticle will evolve into a single broad peak for temperatures T>0, with a broadening that scales as T3/4 at low temperatures and sufficiently weak boson-boson interactions. In the zero-temperature limit, we show that our calculated ground-state polaron energy is in excellent agreement with recent quantum Monte Carlo results and with experiments.
Fuhrer, M., Bao, Q., Culcer, D., Davis, M., Davis, J. A., Hamilton, A., Helmerson, K., Kalantar-Zadeh, K., Klochan, O., Medhekar, N., Ostrovskaya, E., Parish, M., Schiffrin, A., Seidel, J., Sushkov, O., Valanoor, N., Vale, C., Wang, X., Wang, L., Galitskiy, V., Gurarie, V., Hannon, J., Höfling, S., Hone, J., Rule, K. C., Krausz, F., Littlewood, P., MacDonald, A., Neto, A., Oezyilmaz, B., Paglione, J., Phillips, W., Refael, G., Spielman, I., Tadich, A., Xue, Q., Cole, J., Perali, A., Neilson, D., Lin, H., Sek, G., Gaston, N., Hodgkiss, J. M., Tang, M., Karel, J., Nguyen, T. & Adam, S.
Australian Research Council (ARC), Monash University – Internal School Contribution, Monash University – Internal Department Contribution, Monash University – Internal Faculty Contribution, Monash University – Internal University Contribution, University of Wollongong, University of Queensland , Tsinghua University, University of New South Wales, Australian National University , RMIT University, Swinburne University of Technology
29/06/17 → 28/06/24
1/01/17 → 31/12/20