Superfluid current disruption in a chain of weakly coupled Bose–Einstein condensates

Cataliotti, F. S.; Fallani, Leonardo; Ferlaino, Francesca; Fort, C.; Maddaloni, P.; Inguscio, M.

doi:10.1088/1367-2630/5/1/371

Cited by 195 publications

(227 citation statements)

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“…For instance, the possibility of combining a large and well defined de Broglie wavelength together with a density small enough to suppress interactions, should provide the conditions to observe Anderson-like localization [13]. On the other hand, the interacting regime should allow investigation of effects such as the breakdown of superfluidity through obstacles [9,10], or nonlinear resonant transport [11,12]. We thus believe that our scheme constitutes a very promising tool for further development of coherent guided atom optics.…”

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confidence: 91%

“…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.…”

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confidence: 99%

“…Such values are of interest for experiments in atom interferometry as, for instance, the coherent splitting at the crossing of two matterwave guides [29,30], which could be implemented in miniaturized components [31]. Furthermore, as the atomic wavelength reaches values similar to visible light wavelength, transport properties through wells, barriers or disordered structures engineered with light should enter the quantum regime [8,9,10,11,12,13,14]. Also the control of the atom-laser flux offers the possibility to tune the amount of interaction inside the guided atomlaser beam.…”

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confidence: 99%

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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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“…We modulate the radial frequency by 10% of its value. A bigger oscillation amplitude would produce a loss of superfluidity caused by entering regions of unstable dynamics [20]. This procedure excites modes with zero angular momen-…”

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Collective Excitations of a Trapped Bose-Einstein Condensate in the Presence of a 1D Optical Lattice

et al. 2003

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We study low-lying collective modes of a horizontally elongated 87 Rb condensate produced in a 3D magnetic harmonic trap with the addition of a 1D periodic potential which is provided by a laser standing-wave along the horizontal axis. While the transverse breathing mode results unperturbed, quadrupole and dipole oscillations along the optical lattice are strongly modified. The measurement of frequencies of collective modes was immediately recognized to be a fundamental and precise tool to investigate the quantum macroscopic behaviour of atomic Bose-Einstein condensates. The observations of low-lying excitations [1,2,3], including the scissor mode [4], were an important step toward the characterization of these systems. Collective excitations were also studied at finite temperature [5,6,7,8] investigating frequency shifts and damping rates. All the experiments so far reported were performed on Bose-Einstein condensates magnetically trapped in pure harmonic potentials.More recently, condensates trapped in periodic potentials have attracted much interest demonstrated by the flourishing of both theoretical and experimental papers in this field. BEC trapped in a periodic potential is particularly interesting as a possible system for the investigation of pure quantum effects. Many results have been reported e.g. interference of atomic de Broglie waves tunneling from a vertical array of BECs [9], observation of squeezed states in a BEC [10], realization of a linear array of Josephson junctions [11] with BECs, observation of Bloch oscillations [12] and culminating with the observation of the quantum phase transition from a superfluid to a Mott insulator [13]. Recently, the general interest of this field has been extended to a careful study of the loading of BECs in an optical lattice [14] and to the observation of collapse and revival of the matter wave field of a BEC [15]. In this context, the characterization of collective modes of a condensate in the presence of an optical lattice motivated the development of a new theoretical treatment [16] based on a generalization of the hydrodynamic equation of superfluids for a weakly interacting Bose gas [17,18] to include the effects of the periodic potential. The collective modes of a trapped BEC are predicted to be significantly modified by the presence of an optical lattice. Precise measurements of the low-lying collective frequency would verify the validity of the mass renormalization theory [16].In this Letter we quantitatively investigate the modification of the low-lying excitation spectrum of a harmonically trapped BEC, due to the presence of a 1D optical lattice. In particular we measure the frequencies of the quadrupole and transverse breathing modes as a function of the optical lattice depth. The experimental observations are compared with the predictions of the model reported in [16] consisting in a frequency shift of the collective modes characterized by a motion along the lattice axis, whereas the frequency of collective modes involving an atomic flow transverse...

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“…In particular, the superfluid flow of a Bose-Einstein condensate (BEC) loaded on a lattice exhibits a novel instability called dynamical instability that was predicted a decade ago [3,4], which has attracted much attention both theoretically [5][6][7][8] and experimentally [9][10][11][12][13]. The dynamical instability is induced by the interplay between the lattice periodicity and nonlinearity due to the inter-particle interactions in the BEC.…”

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confidence: 99%

Dynamical instability in theS=1Bose-Hubbard model

Asaoka¹,

Tsuchiura²,

Yamashita³

et al. 2016

Phys. Rev. A

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We study the dynamical instabilities of superfluid flows in the S = 1 Bose-Hubbard model. The time evolution of each spin component in a condensate is calculated based on the dynamical Gutzwiller approximation for a wide range of interactions, from a weakly correlated regime to a strongly correlated regime near the Mottinsulator transition. Owing to the spin-dependent interactions, the superfluid flow of the spin-1 condensate decays at a different critical momentum from a spinless case when the interaction strength is the same. We furthermore calculate the dynamical phase diagram of this model and clarify that the obtained phase boundary has very different features depending on whether the average number of particles per site is even or odd. Finally, we analyze the density and spin modulations that appear in association with the dynamical instability. We find that spin modulations are highly sensitive to the presence of a uniform magnetic field.

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Superfluid current disruption in a chain of weakly coupled Bose–Einstein condensates

Cited by 195 publications

References 20 publications

Guided Quasicontinuous Atom Laser

Guided Quasicontinuous Atom Laser

Collective Excitations of a Trapped Bose-Einstein Condensate in the Presence of a 1D Optical Lattice

Dynamical instability in theS=1Bose-Hubbard model

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