Dynamical excitation of maxon and roton modes in a Rydberg-dressed Bose-Einstein condensate

McCormack, Gary; Nath, Rejish; Li, Weibin

Abstract

We investigate the dynamics of a three-dimensional Bose-Einstein condensate of ultracold atomic gases with a soft-core shape long-range interaction, which is induced by laser dressing the atoms to a highly excited Rydberg state. For a homogeneous condensate, the long-range interaction drastically alters the dispersion relation of the excitation, supporting both roton and maxon modes. Rotons are typically responsible for the creation of supersolids, while maxons are normally dynamically unstable in BECs with dipolar interactions. We show that maxon modes in the Rydberg-dressed condensate, on the contrary, are dynamically stable. We find that the maxon modes can be excited through an interaction quench, i.e. turning on the soft-core interaction instantaneously. The emergence of the maxon modes is accompanied by oscillations at high frequencies in the quantum depletion, while rotons lead to much slower oscillations. The dynamically stable excitation of the roton and maxon modes leads to persistent oscillations in the quantum depletion. Through a self-consistent Bogoliubov approach, we identify the dependence of the maxon mode on the soft-core interaction. Our study shows that maxon and roton modes can be excited dynamically and simultaneously by quenching Rydberg-dressed long-range interactions. This is relevant to current studies in creating and probing exotic states of matter with ultracold atomic gases.

• Journal Article Type: Article
• Acceptance Date: Jul 14, 2020
• Online Publication Date: Aug 19, 2020
• Publication Date: Aug 19, 2020
• Deposit Date: Jul 15, 2020
• Publicly Available Date: Aug 19, 2020
• Journal: Physical Review A
• Print ISSN: 2469-9926
• Electronic ISSN: 2469-9934
• Publisher: American Physical Society
• Peer Reviewed: Peer Reviewed
• Volume: 102
• Issue: 2
• Article Number: 023319
• DOI: https://doi.org/10.1103/physreva.102.023319
• Public URL: https://nottingham-repository.worktribe.com/output/4768565
• Publisher URL: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.102.023319