| 1. |
- Yu, Yongle, et al.
(författare)
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Supershell structure in trapped dilute Fermi gases
- 2005
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - : American Physical Society. - 1050-2947 .- 1094-1622. ; 72:5
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Tidskriftsartikel (refereegranskat)abstract
- We show that a dilute harmonically trapped two-component gas of fermionic atoms with a weak repulsive interaction has a pronounced super-shell structure: The shell fillings due to the spherical harmonic trapping potential are modulated by a beat mode. This changes the "magic numbers" occurring between the beat nodes by half a period. The length and amplitude of this beating mode depend on the strength of the interaction. We give a simple interpretation of the beat structure in terms of a semiclassical trace formula for the symmetry breaking U(3)→SO(3).
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| 2. |
- Ögren, Magnus, 1977-, et al.
(författare)
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Atom-atom correlations in colliding Bose-Einstein condensates
- 2009
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - : American Physical Society. - 1050-2947 .- 1094-1622. ; 79:2
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Tidskriftsartikel (refereegranskat)abstract
- We analyze atom-atom correlations in the s -wave scattering halo of two colliding condensates. By developing a simple perturbative approach, we obtain explicit analytic results for the collinear (CL) and back-to-back (BB) correlations corresponding to realistic density profiles of the colliding condensates with interactions. The results in the short-time limit are in agreement with the first-principles simulations using the positive- P representation and provide analytic insights into the experimental observations of Perrin [Phys. Rev. Lett. 99, 150405 (2007)]. For long collision durations, we predict that the BB correlation becomes broader than the CL correlation.
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| 3. |
- Ögren, Magnus, 1977-, et al.
(författare)
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Supershell structures and pairing in ultracold trapped Fermi gases
- 2007
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - : American Physical Society. - 1050-2947 .- 1094-1622. ; 76:2
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Tidskriftsartikel (refereegranskat)abstract
- We calculate level densities and pairing gaps for an ultracold dilute gas of fermionic atoms in harmonic traps under the influence of mean field and anharmonic quartic trap potentials. Supershell nodes, which were found in Hartree-Fock calculations, are calculated analytically within periodic orbit theory as well as from WKB calculations. For attractive interactions, the underlying level densities are crucial for pairing and supershell structures in gaps are predicted.
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| 4. |
- Andersson, Egil, et al.
(författare)
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Single-photon core-valence double ionization of molecular oxygen
- 2008
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 78, s. 023409-
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Tidskriftsartikel (refereegranskat)abstract
- Single-photon core-valence double ionization of molecular oxygen has been studied using a magnetic bottle time-of-flight electron coincidence spectrometer. The K-1V-1 double ionization electron spectrum of O-2 is reported and is assigned with the aid of ab initio calculations. A direct comparison of the core-valence double ionization electron spectra with the conventional valence band photoelectron spectrum is made. The lowest core-valence double ionization energy is found to be 571.6 eV and is associated with a (3)Pi dicationic state.
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| 5. |
- Joshi, C., et al.
(författare)
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Entanglement of distant optomechanical systems
- 2012
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Ingår i: Physical Review A. - 1050-2947 .- 1094-1622. ; 85:3
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Tidskriftsartikel (refereegranskat)abstract
- We theoretically investigate the possibility to generate nonclassical states of optical and mechanical modes of optical cavities, distant from each other. A setup comprised of two identical cavities, each with one fixed and one movable mirror and coupled by an optical fiber, is studied in detail. We show that with such a setup there is potential to generate entanglement between the distant cavities, involving both optical and mechanical modes. The scheme is robust with respect to dissipation, and nonlocal correlations are found to exist in the steady state at finite temperatures.
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| 6. |
- Larson, Jonas, et al.
(författare)
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Spin-orbit-coupled Bose-Einstein condensate in a tilted optical lattice
- 2010
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - : APS. - 1050-2947 .- 1094-1622. ; 82:4, s. 043620-
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Tidskriftsartikel (refereegranskat)abstract
- Bloch oscillations appear for a particle in a weakly tilted periodic potential. The intrinsic spin Hall effect is an outcome of a spin-orbit coupling. We demonstrate that both of these phenomena can be realized simultaneously in a gas of weakly interacting ultracold atoms exposed to a tilted optical lattice and to a set of spatially dependent light fields inducing an effective spin-orbit coupling. It is found that both the spin Hall and the Bloch oscillation effects may coexist, showing, however, a strong correlation between the two. These correlations are manifested as a transverse spin current oscillating in-phase with the Bloch oscillations. On top of the oscillations originating from the periodicity of the model, a trembling motion is found which is believed to be atomic Zitterbewegung. It is argued that the damping of these Zitterbewegung oscillations may to a large extent be prevented in the present setup considering a periodic optical lattice potential.
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| 7. |
- Sorensen, S. L., et al.
(författare)
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Electronic Doppler effect in resonant Auger decay of CO molecules upon excitation near a shake-up Pi resonance
- 2007
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - : APS. - 1050-2947 .- 1094-1622. ; 76:062704
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Tidskriftsartikel (refereegranskat)abstract
- Wepresent an experimental observation of the electronic Doppler effect inresonant Auger spectra upon core excitation slightly above the carbonK edge of the CO molecule. Thus the electronic Dopplereffect has been identified in above-threshold excitation, and in atransition of symmetry. Ab initio calculations of the potentialenergy curves of the relevant states of CO and thewave packet technique have been employed to provide a theoreticalbackground to the experimental studies. The weak feature around 299.4 eVin the photoabsorption spectrum, whose decay has been investigated bythe present experiment, is assigned to double (core-valence) excitations toC 1s shake-up states |1s1−1*2 with a strong dissociative character,and the Doppler splitting of the atomic peak has beenreproduced by the simulation.
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| 8. |
- Ögren, Magnus, et al.
(författare)
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Atom-atom correlations and relative number squeezing in dissociation of spatially inhomogeneous molecular condensates
- 2008
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Ingår i: Physical Review A. - : American Physical Society. ; 78:1
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Tidskriftsartikel (refereegranskat)abstract
- We study atom-atom correlations and relative number squeezing in the dissociation of a Bose-Einstein condensate (BEC) of molecular dimers made of either bosonic or fermionic atom pairs. Our treatment addresses the role of the spatial inhomogeneity of the molecular BEC on the strength of correlations in the short time limit. We obtain explicit analytic results for the density-density correlation functions in momentum space, and show that the correlation widths and the degree of relative number squeezing are determined merely by the shape of the molecular condensate.
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| 9. |
- Ögren, Magnus, et al.
(författare)
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Directional effects due to quantum statistics in dissociation of elongated molecular condensates
- 2009
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Ingår i: Physical Review A. - : American Physical Society. ; 79:4
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Tidskriftsartikel (refereegranskat)abstract
- Ultracold clouds of dimeric molecules can dissociate into quantum mechanically correlated constituent atoms that are either both bosons or both fermions. We theoretically model the dissociation of two-dimensional anisotropic molecular condensates for which this difference manifests as complementary geometric structures of the dissociated atoms. Atomic bosons are preferentially emitted along the long axis of the molecular condensate, while atomic fermions are preferentially emitted along the short axis. This anisotropy potentially simplifies the measurement of correlations between the atoms through relative number squeezing.
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| 10. |
- Ögren, Magnus, 1977-, et al.
(författare)
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Solitary waves in elongated clouds of strongly interacting bosons
- 2005
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - : American Physical Society. - 1050-2947 .- 1094-1622. ; 72:2
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Tidskriftsartikel (refereegranskat)abstract
- We examine the propagation of solitary waves in elongated clouds of trapped bosonic atoms as the confinement, the strength of the interatomic interaction, and the atom density are varied. We identify three different physical regimes and develop a general formalism that allows us to interpolate between them. Finally we pay special attention to the transition to the Tonks-Girardeau limit of strongly interacting bosons.
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