Browsing by Author "Nguyen, J.H.V."
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Item Creation and Characterization of Matter-Wave Breathers(American Physical Society, 2020) Luo, D.; Jin, Y.; Nguyen, J.H.V.; Malomed, B.A.; Marchukov, O.V.; Yurovsky, V.A.; Dunjko, V.; Olshanii, M.; Hulet, R.G.We report the creation of quasi-1D excited matter-wave solitons, “breathers,” by quenching the strength of the interactions in a Bose-Einstein condensate with attractive interactions. We characterize the resulting breathing dynamics and quantify the effects of the aspect ratio of the confining potential, the strength of the quench, and the proximity of the 1D–3D crossover for the two-soliton breather. Furthermore, we demonstrate the complex dynamics of a three-soliton breather created by a stronger interaction quench. Our experimental results, which compare well with numerical simulations, provide a pathway for utilizing matter-wave breathers to explore quantum effects in large many-body systems.Item Parametric Excitation of a Bose-Einstein Condensate: From Faraday Waves to Granulation(American Physical Society, 2019) Nguyen, J.H.V.; Tsatsos, M.C.; Luo, D.; Lode, A.U.J.; Telles, G.D.; Bagnato, V.S.; Hulet, R.G.We explore, both experimentally and theoretically, the response of an elongated Bose-Einstein condensate to modulated interactions. We identify two distinct regimes differing in modulation frequency and modulation strength. Longitudinal surface waves are generated either resonantly or parametrically for modulation frequencies near the radial trap frequency or twice the trap frequency, respectively. The dispersion of these waves, the latter being a Faraday wave, is well reproduced by a mean-field theory that accounts for the 3D nature of the elongated condensate. In contrast, in the regime of lower modulation frequencies, we find that no clear resonances occur, but with an increased modulation strength, the condensate forms an irregular granulated distribution that is outside the scope of a mean-field approach. We find that the granulated condensate is characterized by large quantum fluctuations and correlations, which are well described with single-shot simulations obtained from wave functions computed by a beyond-mean-field theory at zero temperature, the multiconfigurational time-dependent Hartree for bosons method.