Low-Energy Collective Oscillations and Bogoliubov Sound in an Exciton-Polariton Condensate

We report the observation of low-energy, low-momenta collective oscillations an exciton-polariton condensate in a round “box” trap. The are dominated by dipole and breathing modes, ratio frequencies two modes is consistent with that weakly interacting two-dimensional trapped Bose gas. speed sound extracted from oscillation frequency smaller than Bogoliubov sound, which can be partly explained influence incoherent reservoir. These results pave way for understanding effects reservoir, dissipation, energy relaxation, finite temperature on superfluid properties condensates other open-dissipative quantum fluids.Received 28 April 2020Revised 24 August 2020Accepted January 2021DOI:https://doi.org/10.1103/PhysRevLett.126.075301© 2021 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasExciton polaritonQuantum fluids & solidsPhysical SystemsBose-Einstein condensatesPolariton condensateCondensed Matter, Materials Applied Physics