We study nonlinear dynamics of Rydberg-dressed Bose-Einstein condensates (BECs) trapped in a triple-well potential in the semiclassical limit. The Rydberg-dressed BECs experience a long-range soft-core interaction, giving rise to strong nearest and next-nearest neighbor interactions in the triple-well system. Using mean-field Gross-Pitaevskii (GP) equations, we show that lower branches of the eigenspectra exhibit loops and level-crossings when the soft-core interaction is strong. The direct level-crossings eliminate the possibility of adiabatic Landau-Zener transitions when tilting of the triple-well potential. We demonstrate that the long-range interaction allows for self-trapping in one, two, or three wells, in a far more controllable manor than BECs with short-range or dipolar interactions. Exact quantum simulations of the three-well Bose-Hubbard model indicate that selftrapping and nonadiabatic transition can be observed with less than a dozen bosons. Our study is relevant to current research into collective excitation and nonlinear dynamics of Rydberg-dressed atoms.
We construct an exact dynamical mean field theory for nonresonant inelastic light scattering in the infinite-dimensional Falicov-Kimball model, which can be tuned through a quantum critical metal-insulator transition. Due to the projection of the polarization orientations onto different regions of the Brillouin zone and due to the transfer of energy and momentum from the light to the strongly correlated charge excitations, the nature of the dynamics can be naturally interpreted as strongly temperature-dependent low-energy particle-hole excitations and weakly temperature-dependent high-energy charge transfer excitations which depend delicately on the electronic correlations. These results can be used to give important information concerning the evolution of charge dynamics in different regions of the Brillouin zone.Comment: 11 pages, 10 figure
We calculate the inelastic light scattering from X-rays, which allows the photon to transfer both energy and momentum to the strongly correlated charge excitations. We find that the charge transfer peak and the low energy peak both broaden and disperse through the Brillouin zone similar to what is seen in experiments in materials like Ca2CuO2Cl2.PACS numbers: 78.70. Ck, 72.80.Sk, 78.66.Nk, 71.30.+h, 71.27.+a The dynamics of electrons in strongly correlated systems is far from well-understood. In a Mott insulator, correlations split a single band into a lower and an upper Hubbard band separated by a Mott gap. Many experimental probes have focused attention on exploring the detailed nature of the lower Hubbard band from which electrons may be excited using angle-resolved photoemission (ARPES) for example, but the structure and symmetry of the upper Hubbard band and the relaxational dynamics of electrons populated into it remains largely unexplored.Inelastic [6]. The measured signal is resonantly enhanced by tuning the incident photon energy to lie near the Cu K or V L 3 edge. The measurements have revealed remarkably similar characteristics as a function of photon energy loss: (1) the presence of a large, sharp and relatively dispersionless peak centered around a few eVs, and (2) the development of a low energy peak dispersive towards higher frequencies for photon momentum transfers from the Brillouin zone (BZ) center along either the BZ edge or diagonal. Example of the data taken on Ca 2 CuO 2 Cl 2 [3] is shown in Figure 1. The high energy peak has been associated with photon-induced charge transfer between orbitals of different atoms [4] or different orbitals of the same atom [3,6], while the low frequency peak has been associated with a transition from the lower to upper Hubbard band across an effective Mott gap[3, 4, 6] and a q-dependence of the Mott gap has been inferred [2]. However it does not seem obvious why an excitation across a Mott gap would show dispersion given that the physics of the Mott transition is highly local in character.Theoretical calculations on inelastic X-ray scattering have to our knowledge been limited to energy-band model calculations and exact diagonalization studies of small clusters[1]. While energy-band calculations might be appropriate for ground state properties of weakly corre- lated systems they do not adequately address the role of intra-atomic electron correlations which crucially affect properties of the excitation spectra of strongly correlated systems. Exact diagonalization studies of small clusters [3,7] largely focuses on the energy separation between the states excitable by the X-rays such as excitons, and suffers the limitation that the lineshape of the calculated spectra depend sensitively on cluster size due to finite size effects on electron dynamics. Thus it is clearly of interest for formulate a theory for inelastic X-ray scattering which does not suffer from cluster-size effects and is able to properly account for intra-atomic electron correlations.Two impo...
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.
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