Quantum simulation of ultrafast dynamics using trapped ultracold atoms

Senaratne, Ruwan; Rajagopal, Shankari; Shimasaki, Toshihiko; Dotti, Peter; Fujiwara, Kurt; Singh, Kevin; Geiger, Zachary; Weld, David

doi:10.1038/s41467-018-04556-3

Cited by 23 publications

(11 citation statements)

References 56 publications

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“…In this light, colliding ultracold atoms could be used to mimic electrons during atom-atom collisions. Since the dynamics of ultracold atoms take place on much larger time scales, the usually very fast electronic processes could be slowed down [29,46,47], potentially providing in depth insights into the fundamental processes of atom-atom or atom-ion collisions such as projectile ionization [48,49] or charge transfer [50,51].…”

Section: Introductionmentioning

confidence: 99%

Bosonic Quantum Dynamics Following Colliding Potential Wells

Köhler,

Schmelcher

2021

Preprint

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We employ the multi-configuration time-dependent Hartree method for bosons (MCTDHB) in order to investigate the correlated non-equilibrium quantum dynamics of two bosons confined in two colliding and uniformly accelerated Gaussian wells. As the wells approach each other an effective, transient double-well structure is formed. This induces a transient and oscillatory overbarrier transport. We monitor both the amplitude of the intra-well dipole mode in the course of the dynamics as well as the final distribution of the particles between the two wells. For fast collisions we observe an emission process which we attribute to two distinct mechanisms. Energy transfer processes lead to an untrapped fraction of bosons and a resonant enhancement of the deconfinement for certain kinematic configurations can be observed. Despite the comparatively weak interaction strengths employed in this work, we identify strong inter-particle correlations by analyzing the corresponding Von Neumann entropy.

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Section: Introductionmentioning

confidence: 99%

Bosonic Quantum Dynamics Following Colliding Potential Wells

Köhler,

Schmelcher

2021

Preprint

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“…Femtosecond pump-probe experiments on complex solids 1 as well as quantum simulations with cold gases [2][3][4] allow to investigate collective quantum behavior on microscopic timescales. The dynamics of such manyparticle systems often involves processes on vastly different timescales, which is a particular challenge for theoretical simulations.…”

Section: Introductionmentioning

confidence: 99%

Memory truncated Kadanoff-Baym equations

Stahl,

Dasari,

et al. 2021

Preprint

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The Keldysh formalism for nonequilibrium Green's functions is a powerful theoretical framework for the description of the electronic structure, spectroscopy, and dynamics of strongly correlated systems. However, the underlying Kadanoff-Baym equations (KBE) for the two-time Keldysh Green's functions involve a memory kernel which results in a high computational cost for long simulation times tmax, with a cubic scaling of the computation time with tmax. Truncation of the memory kernel can reduce the computational cost to linear scaling with tmax, but the required memory times will depend on the model and the diagrammatic approximation to the self-energy. We explain how a truncation of the memory kernel can be incorporated into the time-propagation algorithm to solve the KBE, and investigate the systematic truncation of the memory kernel for the Hubbard model in different parameter regimes, and for different diagrammatic approximations. The truncation is easier to control within dynamical mean-field solutions, where it is applied to a momentum-independent self-energy. Here, simulation times up to two orders of magnitude longer are accessible both in the weak and strong coupling regime, allowing for a study of long-time phenomena such as the crossover between pre-thermalization and thermalization dynamics.

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“…Introduction.-The elucidation of nonequilibrium states in strongly correlated systems is of great interest since it promises to open a door to the emergence of novel quantum phases. Nonequilibrium quantum manybody states have recently been investigated not only in solids with light and electric fields [1][2][3][4][5][6][7][8][9][10][11][12] but also in trapped ions [13,14], cold atoms [15][16][17], and quantum circuits [18][19][20][21][22][23]. One of the most significant challenges in this field is how to preserve nonequilibrium states, such as the Floquet states [24][25][26], from thermalization [27][28][29][30], for which the realization of many-body localization (MBL) [31][32][33] may hold the key.…”

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confidence: 99%