Many-body excitations and de-excitations in trapped ultracold bosonic clouds

Abstract

We employ the MultiConfiguraional Time-Dependent Hartree for Bosons (MCTDHB) method to study excited states of interacting Bose-Einstein condensates confined by harmonic and double-well trap potentials. Two approaches to access excitations, a static and a dynamic one, have been studied and contrasted. In static simulations the low-lying excitations have been computed by utilizing the LR-MCTDHB method - a linear response theory constructed on-top of a static MCTDHB solution. Complimentary, we propose two dynamic protocols that address excitations by propagating the MCTDHB wave-function. In particular, we investigate dipole-like oscillations induced by shifting the origin of the confining potential and breathing-like excitations by quenching frequency of a parabolic part of the trap. To contrast static predictions and dynamic results we have computed time-evolutions and their Fourier transforms of several local and non-local observables. Namely, we study evolution of the $⟨x(t)⟩$, its variance $\mathrm{Var}(x(t))$, and of a local density computed at a selected position. We found out that the variance is the most sensitive and informative quantity - along with excitations it contains information about the de-excitations even in a linear regime of the induced dynamics. The dynamic protocols are found to access the many-body excitations predicted by the static LR-MCTDHB approach.

arXiv comment20 pages, 8 figures

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Cited by in corpus (12)

• Multiconfigurational time-dependent Hartree approaches for indistinguishable particles
• Quantum dynamical response of ultracold few boson ensembles in finite optical lattices to multiple interaction quenches
• Analysis of a trapped Bose-Einstein condensate in terms of position, momentum, and angular-momentum variance
• Enhanced many-body effects in the excitation spectrum of a weakly-interacting rotating Bose-Einstein condensate
• Bosonic quantum dynamics following a linear interaction quench in finite optical lattices of unit filling
• Many-body quantum dynamics of an asymmetric bosonic Josephson junction
• Many-body effects in the excitation spectrum of weakly-interacting Bose-Einstein condensates in one-dimensional optical lattices
• Longitudinal and transversal resonant tunneling of interacting bosons in a two-dimensional Josephson junction: Mean-field and many-body dynamics
• Condensates in annuli: Dimensionality of the variance
• Spectral Structure and Many-Body Dynamics of Ultracold Bosons in a Double-Well
• Breathing dynamics of the Bose polaron in a species-selective harmonic trap
• Many-body effects in the excitations and dynamics of trapped Bose-Einstein condensates