Quantum Enhancement of the Index of Refraction in a Bose-Einstein Condensate

We discuss the role of diffuse, Mie and cooperative scattering on the radiation pressure force acting on the center of mass of a cloud of cold atoms. Even though a mean-field Ansatz (the 'timed Dicke state'), previously derived from a cooperative scattering approach, has been shown to agree satisfactorily with experiments, diffuse scattering also describes very well most features of the radiation pressure force on large atomic clouds. We compare in detail an incoherent, random walk model for photons and a diffraction approach to the more complete description based on coherently coupled dipoles. We show that a cooperative scattering approach, although it provides a quite complete description of the scattering process, is not necessary to explain the previous experiments on the radiation pressure force.

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“…cle correlations are neglected at this stage [39][40][41][42][43]. This contribution appears in the plain black curve in Fig.…”

Section: Light Radiated From a Large Atomic Cloud And Its Relatimentioning

confidence: 99%

“…Atomic clouds can be described as a dielectrics, at least in the regime of linear optics and neglecting particle-particle correlations [39][40][41][42][43]. It is then possible to use modal expansions to determine the RPF on the center-of-mass of a macroscopic cloud [38,61].…”

Section: Appendix B: Modal Expansionmentioning

confidence: 99%

Collective effects in the radiation pressure force

et al. 2016

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“…This subject is obviously very old, but cold atomic samples afford an opportunity for experiments in unprecedented regimes and in unprecedented detail. Correspondingly, new experiments are emerging rapidly [1][2][3][4][5][6][7][8][9][10]. The measurements of the optical response have been dominated by trapped inhomogeneous atomic ensembles, but also those with atoms confined in a slab geometry are emerging in increasing numbers in both thermal vapor cells using a hot gas [11] and in the ultracold regime [12].…”

Section: Introductionmentioning

confidence: 99%

Exact electrodynamics versus standard optics for a slab of cold dense gas

Javanainen

Ruostekoski

et al. 2017

Phys. Rev. A

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We study light propagation through a slab of cold gas using both the standard electrodynamics of polarizable media and massive atom-by-atom simulations of the electrodynamics. The main finding is that the predictions from the two methods may differ qualitatively when the density of the atomic sample ρ and the wave number of resonant light k satisfy ρk −3 1. The reason is that the standard electrodynamics is a mean-field theory, whereas for sufficiently strong light-mediated dipole-dipole interactions the atomic sample becomes strongly correlated. The deviations from mean-field theory appear to scale with the parameter ρk −3 , and we demonstrate noticeable effects already at ρk −3 10 −2 . In dilute gases and in gases with an added inhomogeneous broadening the simulations show shifts of the resonance lines in qualitative agreement with the predicted Lorentz-Lorenz shift and "cooperative Lamb shift," but the quantitative agreement is unsatisfactory. Our interpretation is that the microscopic basis for the local-field corrections in electrodynamics is not fully understood.

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“…In dense ensembles of cold atoms, also light-mediated interactions between the atoms can lead to drastic and unexpected phenomena [17][18][19][20] as multiple resonant scattering events give rise to a correlated response. Correlations can emerge even for the classical optical regime in the limit of low light intensity (LLI) of an incident laser [21,22], and the quest for observing the effects of strong light-mediated interactions is attracting considerable attention [23][24][25][26][27][28][29][30][31][32][33][34]. Regular arrays of atoms are particularly interesting for the exploration and manipulation of collective optical responses, as more recently studied also in the quantum regime [35][36][37][38][39][40][41][42][43][44][45][46][47].…”

mentioning

confidence: 99%

Superatom Picture of Collective Nonclassical Light Emission and Dipole Blockade in Atom Arrays

2020

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We show that two-time, second-order correlations of scattered photons from planar arrays and chains of atoms display nonclassical features that can be described by a superatom picture of the canonical singleatom g 2 ðτÞ resonance fluorescence result. For the superatom, the single-atom linewidth is replaced by the linewidth of the underlying collective low light-intensity eigenmode. Strong light-induced dipole-dipole interactions lead to a correlated response, suppressed joint photon detection events, and dipole blockade that inhibits multiple excitations of the collective atomic state. For targeted subradiant modes, the nonclassical nature of emitted light can be dramatically enhanced even compared with that of a single atom.

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Quantum Enhancement of the Index of Refraction in a Bose-Einstein Condensate

Cited by 39 publications

References 28 publications

Collective effects in the radiation pressure force

Collective effects in the radiation pressure force

Exact electrodynamics versus standard optics for a slab of cold dense gas

Superatom Picture of Collective Nonclassical Light Emission and Dipole Blockade in Atom Arrays

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