| 1. |
- Andersson, Pontus, 1971, et al.
(författare)
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Observation of the 2S1/2 metastable state in Pt−
- 2009
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Ingår i: PHYSICAL REVIEW A. - 1050-2947. ; 79, s. 022502 -
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Tidskriftsartikel (refereegranskat)abstract
- We have experimentally investigated the structure of the Pt− ion using laser photodetachment threshold spectroscopy. The experiment was conducted using a collinear laser-ion beam apparatus, in which the residual atoms created in the photodetachment process were detected. A p-wave threshold was observed in the photo- detachment spectrum at an energy of 6851͑13͒ cm−1. We conclude that this onset originates from a photode- tachment transition in which the initial state of Pt− is the previously unobserved 5d106s 2S1/2 state and the final state of Pt is the 5d96s 3D3 ground state. The excitation energy of the 2S1/2 state is determined to be 10 289͑13͒ cm−1. This value can be compared with a multiconfiguration Dirac-Fock calculation performed by Thøgersen et al. ͓Phys. Rev. Lett. 76, 2870 ͑1996͔͒, which yielded an excitation energy of 11 301 cm−1. Our data show no indication of the presence of any other state of Pt−. We conclude that the structure of the Pt− ion is now fully known.
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| 2. |
- Andersson, Pontus, 1971, et al.
(författare)
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Radiative lifetimes of metastable states of negative ions
- 2006
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622 .- 2469-9926 .- 2469-9934. ; 73, s. 032705-
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Tidskriftsartikel (refereegranskat)abstract
- We present a technique for measuring the radiative lifetimes of metastable states of negative ions that involves the use of a heavy-ion storage ring. The method has been applied to investigate the radiative decay of the np(3) P-2(1/2) levels of Te-(n=5) and Se-(n=4) and the 3p(3) D-2 state of Si- for which the J=3/2 and 5/2 levels were unresolved. All of these states are metastable and decay primarily by emission of E2 and M1 radiation. Multi Configuration Dirac-Hartree-Fock calculations of rates for the transitions in Te- and Se- yielded lifetimes of 0.45 s and 4.7 s, respectively. The measured values agree well with these predicted values. In the case of the D-2 state of Si-, however, our measurement was only able to set a lower limit on the lifetime. The upper limit of the lifetime that can be measured with our apparatus is set by how long the ions can be stored in the ring, a limit determined by the rate of collisional detachment. Our lower limit of 1 min for the lifetime of the D-2 state is consistent with both the calculated lifetimes of 162 s for the D-2(3/2) level and 27.3 h for the D-2(5/2) level reported by O'Malley and Beck and 14.5 h and 12.5 h, respectively, from our Breit-Pauli calculations.
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| 3. |
- Bilodeau, R. C., et al.
(författare)
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High-charge-state formation following inner-shell photodetachment from S-
- 2005
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Ingår i: Physical Review A. - 1050-2947. ; 72, s. 050701-
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Tidskriftsartikel (refereegranskat)abstract
- The formation of S+, S2+, S3+, and S4+ is observed following inner-shell photodetachment of S–. The photodetachment spectra for all possible ionic products are obtained over a large region of photon energies covering both the 2p and 2s thresholds (S5+, is energetically allowed at the higher photon energies, but not observed), and are placed on an absolute scale. The 2s threshold energy is measured to be 224.6(5) eV, allowing the determination of the neutral atomic S 2s–13s23p5 inner-shell excited state energy for the first time. The S– 2s–13s23p6 2S1/2 state is observed as a Feshbach resonance 2.3(5) eV below the 2s threshold in the S+, S2+, and S3+ product channels.
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| 4. |
- Christensson, J, et al.
(författare)
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Effective-interaction approach to the many-boson problem
- 2009
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Ingår i: Physical Review A - Atomic, Molecular, and Optical Physics. - 2469-9926 .- 2469-9934 .- 1050-2947. ; 79:1, s. 012707-
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Tidskriftsartikel (refereegranskat)abstract
- We show that the convergence behavior of the many-body numerical diagonalization scheme for strongly interacting bosons in a trap can be significantly improved by the Lee-Suzuki method adapted from nuclear physics: One can construct an effective interaction that acts in a space much smaller than the original Hilbert space. In particular for short-ranged forces and strong correlations, the method offers a good estimate of the energy and the excitation spectrum, at a computational cost several orders of magnitude smaller than that required by the standard method.
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| 5. |
- Dobsicek, Miroslav, et al.
(författare)
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Arbitrary accuracy iterative quantum phase estimation algorithm using a single ancillary qubit: A two-qubit benchmark
- 2007
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Ingår i: Physical Review A - Atomic, Molecular, and Optical Physics. - 2469-9926 .- 2469-9934. ; 76
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Tidskriftsartikel (refereegranskat)abstract
- We discuss the implementation of an iterative quantum phase estimation algorithm with a single ancillary qubit. We suggest using this algorithm as a benchmark for multiqubit implementations. Furthermore, we describe in detail the smallest possible realization, using only two qubits, and exemplify with a superconducting circuit. We discuss the robustness of the algorithm in the presence of gate errors, and show that seven bits of precision is obtainable, even with very limited gate accuracies.
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| 6. |
- Gelens, Lendert, et al.
(författare)
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Impact of nonlocal interactions in dissipative systems: Towards minimal-sized localized structures
- 2007
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Ingår i: Physical Review A - Atomic, Molecular, and Optical Physics. - 2469-9926 .- 2469-9934. ; 75:6, s. 063812-
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Tidskriftsartikel (refereegranskat)abstract
- In order to investigate the size limit of spatial localized structures in a nonlinear system, we explore the impact of linear nonlocality on their domains of existence and stability. Our system of choice is an optical microresonator containing an additional metamaterial layer in the cavity, allowing the nonlocal response of the material to become the dominating spatial process. In that case, our bifurcation analysis shows that this nonlocality imposes another limit on the width of localized structures going beyond the traditional diffraction limit.
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| 7. |
- Hansson, Tobias, 1983, et al.
(författare)
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Propagation of partially coherent solitons in saturable logarithmic media: A comparative analysis
- 2009
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Ingår i: Physical Review A - Atomic, Molecular, and Optical Physics. - 2469-9926 .- 2469-9934. ; 80:3, s. 033819-
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Tidskriftsartikel (refereegranskat)abstract
- Dynamic self-similar solutions of the nonlinear Schrodinger equation are derived describing the propagation of partially coherent solitons in media with saturable logarithmic nonlinearity. The analysis is based on both the Wigner and the coherent density formalisms and it is shown that although the approaches involve different analysis, the solutions for the evolution of the physically relevant intensity distributions are equivalent.
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| 8. |
- Kim, A.V., et al.
(författare)
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Extreme nonlinear optics in a Kerr medium: Exact soliton solutions for a few cycles
- 2008
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Ingår i: Physical Review A - Atomic, Molecular, and Optical Physics. - 2469-9926 .- 2469-9934. ; 77, s. 043823 1-6
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Tidskriftsartikel (refereegranskat)abstract
- Exact soliton solutions containing only a few cycles are found within the framework of a nonlinear full wave equation in a Kerr medium. It is proven numerically that they are stable and play a fundamental role in the pulse propagation dynamics. These wave solitons cover the range from the fundamental Schrodinger solitons, which occur for long pulses involving many field oscillations, to extremely short pulses, which contain only one optical period.
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| 9. |
- Kockaert, Pascal, et al.
(författare)
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Negative diffraction pattern dynamics in nonlinear cavities with left-handed materials
- 2006
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Ingår i: Physical Review A - Atomic, Molecular, and Optical Physics. - 2469-9926 .- 2469-9934. ; 74:3, s. 033822-
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Tidskriftsartikel (refereegranskat)abstract
- We study a ring cavity filled with a slab of a right-handed material and a slab of a left-handed material. Both layers are assumed to be nonlinear Kerr media. First, we derive a model for the propagation of light in a left-handed material. By constructing a mean-field model, we show that the sign of diffraction can be made either positive or negative in this resonator, depending on the thicknesses of the layers. Subsequently, we demonstrate that the dynamical behavior of the modulation instability is strongly affected by the sign of the diffraction coefficient. Finally, we study the dissipative structures in this resonator and reveal the predominance of a two-dimensional up-switching process over the formation of spatially periodic structures, leading to the truncation of the homogeneous hysteresis cycle.
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| 10. |
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