| 1. |
- Bargi, Sara, et al.
(author)
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Persistent currents in Bose gases confined in annular traps
- 2010
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In: Physical Review A (Atomic, Molecular and Optical Physics). - 1050-2947. ; 82:4
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Journal article (peer-reviewed)abstract
- We examine the problem of stability of persistent currents in a mixture of two Bose gases trapped in an annular potential. We evaluate the critical coupling for metastability in the transition from quasi-one- to two-dimensional motion. We also evaluate the critical coupling for metastability in a mixture of two species as a function of the population imbalance. The stability of the currents is shown to be sensitive to the deviation from one-dimensional motion.
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| 2. |
- Cavalli, A., et al.
(author)
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Spin-orbit-enhanced Wigner localization in quantum dots
- 2011
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In: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 84:23
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Journal article (peer-reviewed)abstract
- We investigate quantum dots with Rashba spin-orbit coupling in the strongly-correlated regime. We show that the presence of the Rashba interaction enhances the Wigner localization in these systems, making it achievable for higher densities than those at which it is observed in Rashba-free quantum dots. Recurring shapes in the pair distribution functions of the yrast spectrum, which might be associated with rotational and vibrational modes, are also reported.
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| 3. |
- Karabulut, Elife, et al.
(author)
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Spin–orbit-coupled Bose–Einstein-condensed atoms confined in annular potentials
- 2016
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In: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 18
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Journal article (peer-reviewed)abstract
- A spin–orbit-coupled Bose–Einstein-condensed cloud of atoms confined in an annular trapping potential shows a variety of phases that we investigate in the present study. Starting with the non- interacting problem, the homogeneous phase that is present in an untrapped system is replaced by a sinusoidal density variation in the limit of a very narrow annulus. In the case of an untrapped system there is another phase with a striped-like density distribution, and its counterpart is also found in the limit of a very narrow annulus. As the width of the annulus increases, this picture persists qualitatively. Depending on the relative strength between the inter- and the intra-components, interactions either favor the striped phase, or suppress it, in which case either a homogeneous, or a sinusoidal-like phase appears. Interactions also give rise to novel solutions with a nonzero circulation.
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| 4. |
- Malet, Francesc, et al.
(author)
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Kohn-Sham density functional theory for quantum wires in arbitrary correlation regimes
- 2013
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In: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 87:11
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Journal article (peer-reviewed)abstract
- We use the exact strong-interaction limit of the Hohenberg-Kohn energy density functional to construct an approximation for the exchange-correlation term of the Kohn-Sham approach. The resulting exchange-correlation potential is able to capture the features of the strongly correlated regime without breaking the spin or any other symmetry. In particular, it shows "bumps" (or barriers) that give rise to charge localization at low densities and that are a well-known key feature of the exact Kohn-Sham potential for strongly correlated systems. Here, we illustrate this approach for the study of both weakly and strongly correlated model quantum wires, comparing our results with those obtained with the configuration interaction method and with the usual Kohn-Sham local density approximation. DOI: 10.1103/PhysRevB.87.115146
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| 5. |
- Malet, Francesc, et al.
(author)
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Mixtures of Bose gases confined in concentrically coupled annular traps
- 2010
-
In: Physical Review A (Atomic, Molecular and Optical Physics). - 1050-2947. ; 81:1
-
Journal article (peer-reviewed)abstract
- A two-component Bose-Einstein condensate confined in an axially symmetric potential with two local minima, resembling two concentric annular traps, is investigated. The system shows a number of phase transitions that result from the competition between phase coexistence and radial-azimuthal phase separation. The ground-state phase diagram, as well as the rotational properties, including the (meta) stability of currents in this system, is analyzed.
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| 6. |
- Malet, Francesc, et al.
(author)
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Persistent currents in dipolar Bose-Einstein condensates confined in annular potentials
- 2011
-
In: Physical Review A (Atomic, Molecular and Optical Physics). - 1050-2947. ; 84:4
-
Journal article (peer-reviewed)abstract
- We consider a dipolar Bose-Einstein condensate confined in an annular potential, with all the dipoles being aligned along some arbitrary direction. In addition to the dipole-dipole interaction, we also assume a zero-range hard-core potential. We investigate the stability of the system against collapse, as well as the stability of persistent currents as a function of the orientation of the dipoles and of the strength of the hard-core interaction.
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| 7. |
- Malet, Francesc, et al.
(author)
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Rotational properties of dipolar Bose-Einstein condensates confined in anisotropic harmonic potentials
- 2011
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In: Physical Review A (Atomic, Molecular and Optical Physics). - 1050-2947. ; 83:3
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Journal article (peer-reviewed)abstract
- We study the rotational properties of a dipolar Bose-Einstein condensate confined in a quasi-two-dimensional anisotropic trap for an arbitrary orientation of the dipoles with respect to their plane of motion. Within the mean-field approximation, we find that the lowest-energy state of the system depends strongly on the relative strength between the dipolar and the contact interactions, as well as on the size and the orientation of the dipoles and the size and the orientation of the deformation of the trapping potential.
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| 8. |
- Maria Escartin, Jose, et al.
(author)
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Electron localization in few-electron concentric quantum rings
- 2010
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In: Physica E: Low-dimensional Systems and Nanostructures. - : Elsevier BV. - 1386-9477. ; 42:4, s. 841-843
-
Conference paper (peer-reviewed)abstract
- We investigate electron localization in fully spin-polarized few-electron concentric double quantum rings submitted to a perpendicular magnetic field by means of density functional theory and exact diagonalization calculations. The variation of the applied magnetic field turns out to strongly affect the distribution of the electrons in such 'crystallized' configurations. A comparison and discussion on the agreement between the results obtained from both approaches is presented. (C) 2009 Elsevier B.V. All rights reserved.
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| 9. |
- Maria Escartin, Jose, et al.
(author)
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Isomeric electronic states in concentric quantum rings
- 2009
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In: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 79:24
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Journal article (peer-reviewed)abstract
- We show that polarized few-electron concentric double quantum rings display localized states that are the quantum analog of classical equilibrium ones. These states have very similar energies but fairly different angular momenta, constituting a new physical realization of the isomeric states found in nuclear and molecular physics. Their fingerprint is a very soft mode in the infrared-absorption spectrum at nearly the dipole excitation energy of a rigidly rotating N-electron molecule. The yrast line and the infrared-absorption spectrum are discussed for N=4 and 6 electron configurations.
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| 10. |
- Schlagheck, P., et al.
(author)
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Transport and interaction blockade of cold bosonic atoms in a triple-well potential
- 2010
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In: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 12
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Journal article (peer-reviewed)abstract
- We theoretically investigate the transport properties of cold bosonic atoms in a quasi-one-dimensional (1D) triple-well potential that consists of two large outer wells, which act as microscopic source and drain reservoirs, and a small inner well, which represents a quantum-dot-like scattering region. Bias and gate 'voltages' introduce a time-dependent tilt of the triple-well configuration, and are used to shift the energetic level of the inner well with respect to the outer ones. By means of exact diagonalization considering a total number of six atoms in the triple-well potential, we find diamond-like structures for the occurrence of single-atom transport in the parameter space spanned by the bias and gate voltages. We discuss the analogy with Coulomb blockade in electronic quantum dots, and point out how one can infer the interaction energy in the central well from the distance between the diamonds.
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