Low Velocity Quantum Reflection of Bose-Einstein Condensates

Pasquini, T.A.; Saba, Michele; Jo, Gyu-Boong; Shin, Yeong Gil; Ketterle, Wolfgang; Pritchard, David E.; Savas, T. A.; Mulders, N.

doi:10.1103/physrevlett.97.093201

Cited by 169 publications

(215 citation statements)

References 30 publications

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“…Indeed, changing the frequency of the outcoupler allows one to tune the value of the de Broglie wavelength of the atom laser, and adjusting the rf coupler power allows one to independently vary the atom-laser density from the interacting regime to the noninteracting one [17]. In particular, those advantages opens new prospects for studying quantum transport phenomena, as, for instance, quantum reflection [18], where interactions dramatically suppress the reflection probability [19]. Finally, in spite of the lensing effect due to the interaction of the atom laser with the trapped BEC [3,20], adiabatic transverse mode matching results into the excitation of only a small number of transverse modes, and we discuss the possibility of achieving single transverse mode operation.…”

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Guided Quasicontinuous Atom Laser

et al. 2006

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We report the first realization of a guided quasicontinuous atom laser by rf outcoupling a BEC, from a hybrid optomagnetic trap into a horizontal atomic waveguide. This configuration allows us to cancel the acceleration due to gravity and keep the de Broglie wavelength constant at 0.5 µm during 0.1 s of propagation. We also show that our configuration, equivalent to pigtailing an optical fiber to a (photon) semiconductor laser, ensures an intrinsically good transverse mode matching.PACS numbers: 03.75. Pp, 39.20.+q, 42.60.Jf,41.85.Ew The Bose-Einstein condensation of atoms in the lowest level of a trap represents the matter-wave analog to the accumulation of photons in a single mode of a laser cavity. In analogy to photonic lasers, atom lasers can be obtained by outcoupling from a trapped Bose-Einstein condensate (BEC) to free space [1,2,3]. However, since atoms are massive particles, gravity plays an important role in the laser properties: in the case of rf outcouplers, it lies at the very heart of the extraction process [4] and in general, the beam is strongly accelerated downwards, causing a rapid decrease of the de Broglie wavelength. With the growing interest in coherent atom sources for atom interferometry [5,6,7] and new studies of quantum transport phenomena [8,9,10,11,12,13,14] where large and well defined de Broglie wavelength are desirable, a better control of the atomic motion during its propagation is needed. One solution is to couple the atom laser into a horizontal waveguide, so that the effect of gravity is canceled, leading to the realization of a coherent matter wave with constant wavelength.We report in this letter on the realization of such a guided quasicontinuous atom laser, where the coherent source, i.e. the trapped BEC, and the guide are merged together in a hybrid combination of a magnetic Ioffe-Pritchard trap and a horizontally elongated far offresonance optical trap constituting an atomic waveguide (see Fig. 1). The BEC, in a state sensitive to both trapping potentials, is submitted to a rf outcoupler yielding atoms in a state sensitive only to the optical potential, resulting in an atom laser propagating along the weak confining axis of the optical trap. In addition to canceling the effect of gravity, this configuration has several advantages. Firstly, coupling into a guide from a BEC rather than from a thermal sample [15] allows us to couple a significant flux into a small number of transverse modes of the guide. Secondly, the weak longitudinal trapping potential of the guide can be compensated by the antitrapping potential due to the second order Zeeman effect acting onto the outcoupled atoms, resulting in an atom laser with a quasiconstant de Broglie wavelength. Thirdly, using an rf outcoupler rather than releasing a BEC into a guide [14,16] results into quasicontinuous operation, thus insuring sharp linewidth, and gives a better control on the beam parameters. Indeed, changing the frequency of the outcoupler allows one to tune the value of the de Broglie wavelength of the atom...

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Guided Quasicontinuous Atom Laser

et al. 2006

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“…Finally, in a broader context, one expects other situations that generate a scattered atom halo, such as molecular dissociation in a condensate [36,37,[42][43][44][45][46][47][48], atomic parametric down-conversion [4,[49][50][51][52][53], or the interaction of a condensate with barriers and obstacles [54][55][56][57][58], to also be susceptible to the same anisotropy-producing processes. …”

Section: Discussionmentioning

confidence: 99%

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

et al. 2014

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We report the experimental realization of a single-species atomic four-wave mixing process with BoseEinstein-condensate collisions for which the angular distribution of scattered atom pairs is not isotropic, despite the collisions being in the s-wave regime. Theoretical analysis indicates that this anomalous behavior can be explained by the anisotropic nature of the gain in the medium. There are two competing anisotropic processes: classical trajectory deflections due to the mean-field potential and Bose-enhanced scattering which bears similarity to superradiance. We analyze the relative importance of these processes in the dynamical buildup of the anisotropic density distribution of scattered atoms and compare the Bose enhancement effects to those in optically pumped superradiance.

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“…In strong contrast, at smaller distances fluctuations of the potential become larger than its mean, which is consequently no longer representative. In practice, this conclusion is crucial for measurements of quantum reflection [21,[31][32][33][34], and more generally for any measurement of the Casimir force involving heterogeneous materials.…”

Section: Introductionmentioning

confidence: 99%

“…While the effective medium description is in general quite satisfactory for describing dense materials that indeed look homogenous at the typical scales of the Casimir force, this is not necessarily the case for strongly heterogeneous ("disordered") media that are made of many constituting elements ("scatterers") well separated from one another. Examples of such heterogeneous systems include nanoporous materials [21], clouds of cold atoms [22] and, in a slightly different context, corrugated surfaces [23,24].…”

Section: Introductionmentioning

confidence: 99%

Statistical approach to Casimir-Polder potentials in heterogeneous media

2015

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We explore the statistical properties of the Casimir-Polder potential between a dielectric sphere and a three-dimensional heterogeneous medium, by means of extensive numerical simulations based on the scattering theory of Casimir forces. The simulations allow us to confirm recent predictions for the mean and standard deviation of the Casimir potential, and give us access to its full distribution function in the limit of a dilute distribution of heterogeneities. These predictions are compared with a simple statistical model based on a pairwise summation of the individual contributions of the constituting elements of the medium.

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Low Velocity Quantum Reflection of Bose-Einstein Condensates

Cited by 169 publications

References 30 publications

Guided Quasicontinuous Atom Laser

Guided Quasicontinuous Atom Laser

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

Statistical approach to Casimir-Polder potentials in heterogeneous media

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