Robust states of ultracold bosons in tilted optical lattices

Hiller, Moritz; Venzl, Hannah; Zech, Tobias; Oleś, B.; Mintert, Florian; Buchleitner, Andreas

doi:10.1088/0953-4075/45/9/095301

Cited by 10 publications

(16 citation statements)

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“…In conclusion, in the present contribution we have shown for the first time in the context of BECs in a tilted lattice a relevant phenomenon: the occurrence of a cascade of bifurcation points in the energy spectrum on the emergence of the nonlinear dynamics, where the associated stationary solutions are localized on few lattice's sites. This fact gives a theoretical justification of the chaotic behavior for large nonlinearity, and it agrees with previous numerical predictions [16][17][18][19][20][21]. We think that the present contribution, with the new result of the existence of bifurcation trees, may give a substantially advance in the understanding of the occurrence of quasiclassical chaos for BECs in a tilted lattice.…”

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confidence: 90%

Bifurcation trees of Stark-Wannier ladders for accelerated Bose-Einstein condensates in an optical lattice

Sacchetti

2017

Phys. Rev. E

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In this paper we show that in the semiclassical regime of periodic potential large enough, the Stark-Wannier ladders become a dense energy spectrum because of a cascade of bifurcations while increasing the ratio between the effective nonlinearity strength and the tilt of the external field; this fact is associated to a transition from regular to quantum chaotic dynamics. The sequence of bifurcation points is explicitly given.

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confidence: 90%

Bifurcation trees of Stark-Wannier ladders for accelerated Bose-Einstein condensates in an optical lattice

Sacchetti

2017

Phys. Rev. E

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“…Mean value and standard deviation of the original diagonal matrix elements: = H 278 and Δ = H 141. an interesting subject for future studies. These inherent hidden symmetries emerge locally in the conformation space of 3D random networks and are, in this respect, reminiscent of local symmetries in complex and/or chaotic quantum systems [18,51,52]. While such local symmetries are typically not given by explicitly defined integrals of motion and therefore are hard to detect, they may nonetheless dramatically impact the systemʼs dynamical properties [51,53].…”

Section: Discussionmentioning

confidence: 99%

Centrosymmetry enhances quantum transport in disordered molecular networks

et al. 2014

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For more than 50 years we have known that photosynthetic systems harvest solar energy with almost unit quantum efficiency. However, recent experimental evidence of quantum coherence during the excitonic energy transport in photosynthetic organisms challenges our understanding of this fundamental biological function. Currently, and despite numerous efforts, the causal connection between coherence and efficiency is still a matter of debate. We show, through extensive simulations of quantum coherent transport on networks, that three dimensional structures characterized by centro-symmetric Hamiltonians are statistically more efficient than random arrangements. Moreover, a strong correlation of centro-symmetry with quantum efficiency is also observed under the coherent transport dynamics induced by experimentally estimated electronic Hamiltonians of the Fenna-Mathew-Olson complex of sulfur bacteria and of the cryptophyte PC645 complex of marine algae. The application of a genetic algorithm results in a set of optimized Hamiltonians only when seeded from the experimentally estimated Hamiltonian. These results suggest that what appears to be geometrically disordered complexes may well exhibit an inherent hidden symmetry which enhances the energy transport between chromophores. We are confident that our results will motivate research to explore the properties of nearly centro-symmetric Hamiltonians in realistic environments, and to unveil Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. c fs) [13] shorter than the experimentally reported ones ( ∼ t 660 c fs) [5] at T = 77 K. More recent numerical approaches [14,15] appear to reproduce the experimental findings. Yet, since the experimental results were obtained by measurements on ensembles of individually slightly different molecules, the coherence time for a single molecule would actually be expected to be significantly longer (see, e.g., [16,17] for a discussion on this subject), so that, in the light of these diverse observations, the case appears to be open for further debate. One reason being that the complexity of the quantum New J. Phys. 16 (2014) 055002 T Zech et al New J. Phys. 16 (2014) 055002 T Zech et al 3 3Indeed, we will therefore come up here with a deliberately simple and somewhat abstract model, which restricts the Hamiltonian description of the system to a single excitation of the electronic degrees of freedom on a graph-like configuration space. The influence of the-possibly strongly coupled-vibrational degrees of freedom will be accounted for phenomenologically, by statistical sampling over the graph conformation. New J. Phys. 16 (2014) 055002 T Zech et al 4 4 While the isotropic model here employed can be extended to account for different dipolar orientations, weverified that this does not qualitatively change the results presented below (see also [30]). The same is tru...

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“…The desired dynamical stability may follow from the robustness of the state structure against perturbations in the Hamiltonian parameters. Remarkably, such an example was found recently in the tilted Bose-Hubbard model [18][19][20], for which a set of states that are strongly localized in Fock and real space, and well embedded in the energy spectrum, exhibited a significant stability to dynamical changes in the tilt strength.…”

Section: Introductionmentioning

confidence: 85%

Fock Space Localization of Many-Body States in the Tilted Bose-Hubbard Model

2019

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We analyze the eigenstates' Fock space structure in the tilted Bose-Hubbard Hamiltonian. Fock space localization is quantified in terms of finite-size generalized fractal dimensions. This approach allows us to monitor the parametric evolution of localization across avoided crossings in the energy spectrum. We identify a manifold of strongly localized eigenstates, both in Fock and configuration space, which persists in regimes where all system parameters (hopping, interaction, and tilt strengths) are comparable. For a fixed number of bosons, the localization properties of that manifold are independent of the lattice size. The influence of avoided crossings on the structure of the localized manifold is discussed in detail.

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Robust states of ultracold bosons in tilted optical lattices

Cited by 10 publications

References 55 publications

Bifurcation trees of Stark-Wannier ladders for accelerated Bose-Einstein condensates in an optical lattice

Bifurcation trees of Stark-Wannier ladders for accelerated Bose-Einstein condensates in an optical lattice

Centrosymmetry enhances quantum transport in disordered molecular networks

Fock Space Localization of Many-Body States in the Tilted Bose-Hubbard Model

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