Anisotropy in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>s</mml:mi></mml:math>-wave Bose-Einstein condensate collisions and its relationship to superradiance

Deuar, P.; Jaskula, Jean-Christophe; Bonneau, Marie; Krachmalnicoff, Valentina; Boiron, Denis; Westbrook, Christoph I; Kheruntsyan, K. V.

doi:10.1103/physreva.90.033613

Cited by 13 publications

(14 citation statements)

References 61 publications

(113 reference statements)

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“…If deemed negligible, then integration by parts is justified. In (43) we can now identify a distribution P (λ, t) = [β k − ∂ ∂α k ]P + (λ, t) to act on with (27). Doing so gives:…”

Section: T) (41)mentioning

confidence: 99%

Multi-time correlations in the positive-P, Q, and doubled phase-space representations

Deuar

2021

Quantum

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A number of physically intuitive results for the calculation of multi-time correlations in phase-space representations of quantum mechanics are obtained. They relate time-dependent stochastic samples to multi-time observables, and rely on the presence of derivative-free operator identities. In particular, expressions for time-ordered normal-ordered observables in the positive-P distribution are derived which replace Heisenberg operators with the bare time-dependent stochastic variables, confirming extension of earlier such results for the Glauber-Sudarshan P. Analogous expressions are found for the anti-normal-ordered case of the doubled phase-space Q representation, along with conversion rules among doubled phase-space s-ordered representations. The latter are then shown to be readily exploited to further calculate anti-normal and mixed-ordered multi-time observables in the positive-P, Wigner, and doubled-Wigner representations. Which mixed-order observables are amenable and which are not is indicated, and explicit tallies are given up to 4th order. Overall, the theory of quantum multi-time observables in phase-space representations is extended, allowing non-perturbative treatment of many cases. The accuracy, usability, and scalability of the results to large systems is demonstrated using stochastic simulations of the unconventional photon blockade system and a related Bose-Hubbard chain. In addition, a robust but simple algorithm for integration of stochastic equations for phase-space samples is provided.

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Section: T) (41)mentioning

confidence: 99%

Multi-time correlations in the positive-P, Q, and doubled phase-space representations

Deuar

2021

Quantum

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“…Many essential features of the jets are characterized by their correlations [12][13][14][15][16][17][18][19][20]23]. Specifically, we calculate the angular correlation function,…”

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Collective emission of matter-wave jets from driven Bose–Einstein condensates

Clark

Gaj

Feng

et al. 2017

Nature

106

124

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Scattering is used to probe matter and its interactions in all areas of physics. In ultracold atomic gases, control over pairwise interactions enables us to investigate scattering in quantum many-body systems. Previous experiments on colliding Bose-Einstein condensates have revealed matter-wave interference, haloes of scattered atoms, four-wave mixing and correlations between counter-propagating pairs. However, a regime with strong stimulation of spontaneous collisions analogous to superradiance has proved elusive. In this regime, the collisions rapidly produce highly correlated states with macroscopic population. Here we find that runaway stimulated collisions in Bose-Einstein condensates with periodically modulated interaction strength cause the collective emission of matter-wave jets that resemble fireworks. Jets appear only above a threshold modulation amplitude and their correlations are invariant even when the number of ejected atoms grows exponentially. Hence, we show that the structures and atom occupancies of the jets stem from the quantum fluctuations of the condensate. Our findings demonstrate the conditions required for runaway stimulated collisions and reveal the quantum nature of matter-wave emission.

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“…This is driven by their potential utility in quantum technologies such as precision atom interferometry [1][2][3][4][5] and quantum simulation [6][7][8], as well as fundamental tests of quantum mechanics such as atomic EPR entanglement [9][10][11], the atomic Hong-Ou-Mandel effect [12][13][14] and demonstrations of a Bell inequality using motional degrees of freedom and massive particles [15][16][17][18][19]. Essential to each of these applications has been the ability to well characterise, both theoretically and experimentally, the nature of these atom-pairs as well as their intrinsic correlations [12,[20][21][22][23][24][25][26][27][28][29][30][31][32][33] Recent experiments involving atom-pairs have relied on protocols which can be reduced to the archetypal process of four-wave mixing: A pair of atoms in a coherent Bose-Einstein condensate (BEC) interact and are scattered into a distinct pair of modes (in terms of either spatial, motional or internal degrees of freedom) outside the condensate. Consequently, the vast majority of theoretical work in the literature pertaining to twin-atom production has focused on this case of scattering from a coherent source [14,19,20,24,25,27].…”

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confidence: 99%

Atomic twin beams and violation of a motional-state Bell inequality from a phase-fluctuating quasicondensate source

Lewis-Swan

Kheruntsyan

2020

Phys. Rev. A

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We investigate the dynamics of atomic twin beams produced from a phase-fluctuating source, specifically a 1D Bose gas in the quasi-condensate regime, motivated by the experiment reported in Nature Physics 7, 608 (2011). A short-time analytic model is constructed, which is a modified version of the undepleted pump approximation widely used in quantum and atom optics, except that here we take into account the initial phase fluctuations of the pump source as opposed to assuming long-range phase coherence. We use this model to make quantitative and qualitative predictions of how phase-fluctuations of the source impact the two-particle correlations of scattered atom-pairs. The model is benchmarked against detailed numerical simulations using stochastic phase-space methods, and is shown to validate the intuitive notion that the broadening of momentum-space correlation functions between atoms scattered from a quasi-condensate is driven by the broadened momentum width of the source compared to a true phase coherent condensate. Finally, we combine these theoretical tools and results to investigate the effect phase fluctuations of the twin-beam source can have on a proposed demonstration of a violation of a Bell inequality, which intrinsically relies on phase-sensitive pair correlations. arXiv:2002.01998v1 [cond-mat.quant-gas]

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Anisotropy ins-wave Bose-Einstein condensate collisions and its relationship to superradiance

Cited by 13 publications

References 61 publications

Multi-time correlations in the positive-P, Q, and doubled phase-space representations

Multi-time correlations in the positive-P, Q, and doubled phase-space representations

Collective emission of matter-wave jets from driven Bose–Einstein condensates

Atomic twin beams and violation of a motional-state Bell inequality from a phase-fluctuating quasicondensate source

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