Observation of a Lee-Huang-Yang Fluid

Publikation: Working paperForskning

We observe monopole oscillations in a mixture of Bose-Einstein condensates, where the usually dominant mean-field interactions are canceled. In this case, the system is governed by the next-order Lee-Huang-Yang (LHY) correction to the ground state energy, which describes the effect of quantum fluctuations. Experimentally such a LHY fluid is realized by controlling the atom numbers and interaction strengths in a $^{39}$K spin mixture confined in a spherical trap potential. We measure the monopole oscillation frequency as a function of the LHY interaction strength as proposed recently by J{\o}rgensen et al. [Phys. Rev. Lett. 121, 173403 (2018)] and find excellent agreement with simulations of the complete experiment including the excitation procedure and inelastic losses. This confirms that the system and its collective behavior are dominated by LHY interactions. Moreover, the monopole oscillation frequency is found to stable be against variations of the involved scattering lengths in a broad region around the ideal ones, confirming the dominant, stabilizing effect of the LHY interaction. These results pave the way for using the non-linearity provided by the LHY term in quantum simulation experiments and for investigations beyond the LHY regime.
StatusUdgivet - nov. 2020

Bibliografisk note

6 pages, 4 figures


  • cond-mat.quant-gas, physics.atom-ph

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