Kinetics of Bose-Einstein condensation in a dimple potential

Dutta, Shovan; Mueller, Erich J.

doi:10.1103/physreva.91.013601

Cited by 9 publications

(5 citation statements)

References 61 publications

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“…In the steady state, the 6.9(4) × 10 5 atoms in the dimple are maintained at a low temperature ( T D = 1.08(3) μK) by thermalization through collisions with the 7.3(1.8) × 10 5 laser-cooled atoms in the reservoir 43 . The dimple provides a local density boost thanks to its increased depth (7 μK) and small volume compared with the reservoir 46 – 48 . This leads to a sufficient phase-space density for condensation.…”

Section: Methodsmentioning

confidence: 99%

Continuous Bose–Einstein condensation

Chen

Escudero

Minář

et al. 2022

Nature

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Bose–Einstein condensates (BECs) are macroscopic coherent matter waves that have revolutionized quantum science and atomic physics. They are important to quantum simulation1 and sensing2,3, for example, underlying atom interferometers in space4 and ambitious tests of Einstein’s equivalence principle5,6. A long-standing constraint for quantum gas devices has been the need to execute cooling stages time-sequentially, restricting these devices to pulsed operation. Here we demonstrate continuous Bose–Einstein condensation by creating a continuous-wave (CW) condensate of strontium atoms that lasts indefinitely. The coherent matter wave is sustained by amplification through Bose-stimulated gain of atoms from a thermal bath. By steadily replenishing this bath while achieving 1,000 times higher phase-space densities than previous works7,8, we maintain the conditions for condensation. Our experiment is the matter wave analogue of a CW optical laser with fully reflective cavity mirrors. This proof-of-principle demonstration provides a new, hitherto missing piece of atom optics, enabling the construction of continuous coherent-matter-wave devices.

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Section: Methodsmentioning

confidence: 99%

Continuous Bose–Einstein condensation

Chen

Escudero

Minář

et al. 2022

Nature

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“…In particular, periodic addition of a focused 'dimple' potential [47] allows for the repeated crossing between ther-mal cloud and BEC. Studies to date have only employed this effect in combination with individual, destructive absorption images: BEC production was characterized [48][49][50] and in one pioneering experiment multiple crossings explored [51].…”

Section: Multiple Crossing Of the Phase Transitionmentioning

confidence: 99%

Measurement-enhanced determination of BEC phase transitions

Bason¹,

Heck²,

Napolitano³

et al. 2018

J. Phys. B: At. Mol. Opt. Phys.

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We demonstrate how dispersive atom number measurements during evaporative cooling can be used for enhanced determination of the parameter dependence of the transition to a Bose-Einstein condensate (BEC). In this way shot-to-shot fluctuations in initial conditions are detected and the information extracted per experimental realization is increased. We furthermore calibrate in-situ images from dispersive probing of a BEC with corresponding absorption images in time-of-flight. This allows for the determination of the transition point in a single experimental realization by applying multiple dispersive measurements. Finally, we explore the continuous probing of several consecutive phase transition crossings using the periodic addition of a focused "dimple" potential.Quantum effects have become increasingly important in the development of modern technologies and have led to the need for accurate quantum simulation [1,2]. Various approaches, including cold atoms [3-5] and ions [6], superconducting circuits [7], and photons [8] are used to perform such simulations. In particular, many quantum simulators aim to pin down the boundaries between discrete phases of many-body systems, such as Ising spin transition points [4,6] or magnetic phases [5], with the highest possible accuracy. Current simulations focus on providing tight experimental bounds for benchmarking theoretical models, such as finite temperature bosonic superfluids in optical lattices [9].In this article we investigate the potential for using dispersive probing of ultracold atom clouds in two distinct toymodel settings to enhance future quantum simulations. First, we demonstrate that benchmark probes of thermal clouds during forced evaporative cooling can be used to enhance the accuracy in determining the critical point, at which the transition to a Bose-Einstein condensate (BEC) occurs. Second, we investigate multiple, in-situ probing of BECs during evaporation as a means of single-shot mapping of a phase transition.Since the pioneering work on dispersive probing [10,11], it has been employed to investigate the relative repulsion of BECs and thermal clouds [12] and to monitor the formation of a BEC [13,14] as well as the appearance and dynamics of solitons [15,16]. In-sequence benchmark measurements of cold atomic clouds have recently been applied as a tool to moderately reduce classical fluctuations in atom number [17]. Using active feedback, atom number stabilization of cold clouds to the 10 −3 level was demonstrated in Ref. [18]. However, to date no experiments have explored benchmark-measurement enhanced evaluation of the BEC atom number. Efficient suppression of classical fluctuations could enable the settlement of long-standing theoretical disputes concerning the nature * M. G. Bason and R. Heck contributed equally to this work † Electronic address: sherson@phys.au.dk of fundamental fluctuations arising at the BEC phase transition [19]. In recent years, theoretical studies on dispersive lightmatter interaction based Quantum Non-Demolition (QND) measure...

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“…Jacob et al [66] produced in it a BEC of sodium atoms. Theoretically, it has been proposed [57] and used [21,59] to model the kinetics of BEC [81] as well as in an analysis of a BEC in an optical cavity driven by an external beam [10]. The latter work demonstrated that the essential features of the chaotic behavior of a BEC are low-dimensional.…”

Section: A Motivationmentioning

confidence: 99%

Conditions for order and chaos in the dynamics of a trapped Bose-Einstein condensate in coordinate and energy space

Sakhel

Ghassib

et al. 2016

Eur. Phys. J. D

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We investigate numerically conditions for order and chaos in the dynamics of an interacting BoseEinstein condensate (BEC) confined by an external trap cut off by a hard-wall box potential. The BEC is stirred by a laser to induce excitations manifesting as irregular spatial and energy oscillations of the trapped cloud. Adding laser stirring to the external trap results in an effective time-varying trapping frequency in connection with the dynamically changing combined external+laser potential trap. The resulting dynamics are analyzed by plotting their trajectories in coordinate phase space and in energy space. The Lyapunov exponents are computed to confirm the existence of chaos in the latter space. Quantum effects and trap anharmonicity are demonstrated to generate chaos in energy space, thus confirming its presence and implicating either quantum effects or trap anharmonicity as its generator. The presence of chaos in energy space does not necessarily translate into chaos in coordinate space. In general, a dynamic trapping frequency is found to promote chaos in a trapped BEC. An apparent means to suppress chaos in a trapped BEC is achieved by increasing the characteristic scale of the external trap with respect to the condensate size.

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Kinetics of Bose-Einstein condensation in a dimple potential

Cited by 9 publications

References 61 publications

Continuous Bose–Einstein condensation

Continuous Bose–Einstein condensation

Measurement-enhanced determination of BEC phase transitions

Conditions for order and chaos in the dynamics of a trapped Bose-Einstein condensate in coordinate and energy space

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