A nonadiabatic semi-classical method for dynamics of atoms in optical lattices

Jonsell, Svante; Dion, Claude M.; Nylén, Mats; Petra, S.J.H.; Sjölund, Peder; Kastberg, Anders

doi:10.1140/epjd/e2006-00082-6

Cited by 8 publications

(16 citation statements)

References 20 publications

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“…To emphasize this, we qualitatively reproduce our data with a simplified classical simulation, as well as with a careful semi-classical Monte-Carlo simulation of the laser cooling setup. Our results also evidence the 'stop-and-go' nature of the dynamics of the atoms, where they continuously exchange between being trapped in potential wells and travelling over many wells [24,27,28,30].…”

Section: Discussionsupporting

confidence: 53%

“…Furthermore, the deeper the potentials are, the larger the portion of atoms that are trapped, but even for very shallow potentials the majority of the atoms are trapped. Or, correspondingly, one atom spends most of its time being trapped, interrupted by short periods of inter-well flight [24,27,28,30], where it can travel over several wells.…”

Section: A Laser Coolingmentioning

confidence: 99%

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Fluctuation-induced drift in a gravitationally tilted optical lattice

et al. 2010

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Experimental and theoretical studies are made of Brownian particles trapped in a periodic potential, which is very slightly tilted due to gravity. In the presence of fluctuations, these will trigger a measurable average drift along the direction of the tilt. The magnitude of the drift varies with the ratio between the bias force and the trapping potential. This can be closely compared to a theoretical model system, based on a Fokker-Planck-equation formalism. We show that the level of control and measurement precision we have in our system, which is based on cold atoms trapped in a 3D dissipative optical lattice, makes the experimental setup suitable as a testbed for fundamental statistical physics. We simulate the system with a very simplified and general classical model, as well as with an elaborate semi-classical Monte-Carlo simulation. In both cases, we achieve good qualitative agreement with experimental data.

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Section: Discussionsupporting

confidence: 53%

Section: A Laser Coolingmentioning

confidence: 99%

Fluctuation-induced drift in a gravitationally tilted optical lattice

et al. 2010

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“…2 and T c /T h = 10. The main source of discrepancy between the measured and predicted values stems from the oversimplified model used to determine f c,h [24]. Instead, we can consider this approach to represent a new technique for independently determining f c,h , as our method is particularly sensitive to the small cold fraction and works in the region I p ≪ I d .…”

Section: Transient Responsementioning

confidence: 99%

Bunching-induced optical nonlinearity and instability in cold atoms [Invited]

Greenberg¹,

Schmittberger²,

Gauthier³

2011

Opt. Express

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Abstract:We report a new nonlinear optical process that occurs in a cloud of cold atoms at low-light-levels when the incident optical fields simultaneously polarize, cool, and spatially-organize the atoms. We observe an extremely large effective fifth-order nonlinear susceptibility of χ (5) = 7.6 × 10 −15 (m/V) 4 , which results in efficient Bragg scattering via six-wave mixing, slow group velocities (∼ c/10 5 ), and enhanced atomic coherence times (> 100 µs). In addition, this process is particularly sensitive to the atomic temperatures, and provides a new tool for in-situ monitoring of the atomic momentum distribution in an optical lattice. For sufficiently large light-matter couplings, we observe an optical instability for intensities as low as ∼ 1 mW/cm 2 in which new, intense beams of light are generated and result in the formation of controllable transverse optical patterns.

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“…The method outlined in this section was tested against simple analytic models and by comparison against previously published work looking at polarization gradient cooling in one-dimensional dissipative optical lattices [13][14][15]. The results agree very well for intermediate saturation parameters.…”

Section: Methodsmentioning

confidence: 90%

“…In the semi-classical approximation the external degrees of freedom of the atom are treated classically, while the internal degrees of freedom are treated quantum mechanically. The semi-classical approximation is used in most theoretical treatments of polarization gradient cooling [10,13,14,17,19]. The approximation can be used in situations in which the coherence length of the atomic ensemble is much less than a wavelength; it relies on the dephasing influence of spontaneous emission to in effect 'localize' the atoms.…”

Section: F the Semi-classical Approximationmentioning

confidence: 99%

Large-photon-number extraction from individual atoms trapped in an optical lattice

Shotter

2011

Phys. Rev. A

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The atom-by-atom characterization of quantum gases requires the development of novel measurement techniques. One particularly promising new technique demonstrated in recent experiments uses strong fluorescent laser scattering from neutral atoms confined in a short-period optical lattice to measure the position of individual atoms in the sample. A crucial condition for the measurements is that atomic hopping between lattice sites must be strongly suppressed despite substantial photon recoil heating. This article models three-dimensional polarization gradient cooling of atoms trapped within a far-detuned optical lattice. The atomic dynamics are simulated using a hybrid Monte Carlo and master equation analysis in order to predict the frequency of processes which give rise to degradation or loss of the fluorescent signal during measurements. It is shown, consistent with the experimental results, that there exists a wide parameter range in which the lifetime of strongly-fluorescing isolated lattice-trapped atoms is limited by background gas collisions rather than radiative processes. In these cases the total number of scattered photons can be as large as 10 8 per atom. The performance of the technique is related to relevant experimental parameters.

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A nonadiabatic semi-classical method for dynamics of atoms in optical lattices

Cited by 8 publications

References 20 publications

Fluctuation-induced drift in a gravitationally tilted optical lattice

Fluctuation-induced drift in a gravitationally tilted optical lattice

Bunching-induced optical nonlinearity and instability in cold atoms [Invited]

Large-photon-number extraction from individual atoms trapped in an optical lattice

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