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| 2. |
- Gisselbrecht, M., et al.
(författare)
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Attosecond insight into electron correlation
- 2019
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Ingår i: Proceedings 2015 European Conference on Lasers and Electro-Optics - European Quantum Electronics Conference, CLEO/Europe-EQEC 2015. - 9781467374750
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Konferensbidrag (refereegranskat)abstract
- Photoionization with a single photon is one of the fundamental processes in nature, in which one electron is ripped away from its atom. Traditionally studied in the energy domain, this process was believed to be instantaneous, but recent advances in the production of attosecond pulses (1 as 10−18 s) in the eXtreme UltraViolet (XUV) have renewed interest in understanding the temporal aspects of electron emission in atoms, molecules and the solid state [1–8]. We present here our progress in understanding the influence of electronic correlations on the attosecond photoionization dynamics.
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| 3. |
- Barillot, T., et al.
(författare)
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Angular asymmetry and attosecond time delay from the giant plasmon resonance in C60 photoionization
- 2015
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 91
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Tidskriftsartikel (refereegranskat)abstract
- This combined experimental and theoretical study demonstrates that the surface plasmon resonance in C 60 alters the valence photoemission quantum phase, resulting in strong effects in the photoelectron angular distribution and emission time delay. Electron momentum imaging spectroscopy is used to measure the photoelectron angular distribution asymmetry parameter that agrees well with our calculations from the time-dependent local density approximation (TDLDA). Significant structure in the valence photoemission time delay is simultaneously calculated by TDLDA over the plasmon active energies. Results reveal a unified spatial and temporal asymmetry pattern driven by the plasmon resonance and offer a sensitive probe of electron correlation. A semiclassical approach facilitates further insights into this link that can be generalized and applied to other molecular systems and nanometer-sized metallic materials exhibiting plasmon resonances.
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| 4. |
- Horio, M., et al.
(författare)
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Three-Dimensional Fermi Surface of Overdoped La-Based Cuprates
- 2018
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Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 121:7
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Tidskriftsartikel (refereegranskat)abstract
- We present a soft x-ray angle-resolved photoemission spectroscopy study of overdoped high-temperature superconductors. In-plane and out-of-plane components of the Fermi surface are mapped by varying the photoemission angle and the incident photon energy. No k(z) dispersion is observed along the nodal direction, whereas a significant antinodal k(z) dispersion is identified for La-based cuprates. Based on a tight-binding parametrization, we discuss the implications for the density of states near the van Hove singularity. Our results suggest that the large electronic specific heat found in overdoped La2-xSrxCuO4 cannot be assigned to the van Hove singularity alone. We therefore propose quantum criticality induced by a collapsing pseudogap phase as a plausible explanation for observed enhancement of electronic specific heat.
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| 5. |
- Hugosson, Jonas, 1955, et al.
(författare)
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A 16-yr Follow-up of the European Randomized study of Screening for Prostate Cancer
- 2019
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Ingår i: European Urology. - : Elsevier BV. - 0302-2838. ; 76:1, s. 43-51
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Tidskriftsartikel (refereegranskat)abstract
- Background: The European Randomized study of Screening for Prostate Cancer (ERSPC) has previously demonstrated that prostate-specific antigen (PSA) screening decreases prostate cancer (PCa) mortality. Objective: To determine whether PSA screening decreases PCa mortality for up to 16 yr and to assess results following adjustment for nonparticipation and the number of screening rounds attended. Design, setting, and participants: This multicentre population-based randomised screening trial was conducted in eight European countries. Report includes 182 160 men, followed up until 2014 (maximum of 16 yr), with a predefined core age group of 162 389 men (55-69 yr), selected from population registry. Outcome measurements and statistical analysis: The outcome was PCa mortality, also assessed with adjustment for nonparticipation and the number of screening rounds attended. Results and limitations: The rate ratio of PCa mortality was 0.80 (95% confidence interval [CI] 0.72-0.89, p < 0.001) at 16 yr. The difference in absolute PCa mortality increased from 0.14% at 13 yr to 0.18% at 16 yr. The number of men needed to be invited for screening to prevent one PCa death was 570 at 16 yr compared with 742 at 13 yr. The number needed to diagnose was reduced to 18 from 26 at 13 yr. Men with PCa detected during the first round had a higher prevalence of PSA >20 ng/ml (9.9% compared with 4.1% in the second round, p < 0.001) and higher PCa mortality (hazard ratio = 1.86, p < 0.001) than those detected subsequently. Conclusions: Findings corroborate earlier results that PSA screening significantly reduces PCa mortality, showing larger absolute benefit with longer follow-up and a reduction in excess incidence. Repeated screening may be important to reduce PCa mortality on a population level. Patient summary: In this report, we looked at the outcomes from prostate cancer in a large European population. We found that repeated screening reduces the risk of dying from prostate cancer. (C) 2019 Published by Elsevier B.V. on behalf of European Association of Urology.
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| 6. |
- Sassa, Yasmine, et al.
(författare)
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The metallic quasi-1D spin-density-wave compound NaV2O4 studied by angle-resolved photoelectron spectroscopy
- 2018
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Ingår i: Journal of Electron Spectroscopy and Related Phenomena. - : ELSEVIER SCIENCE BV. - 0368-2048 .- 1873-2526. ; 224, s. 79-83
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Tidskriftsartikel (refereegranskat)abstract
- Angle-resolved photoelectron spectroscopy has been used to follow the valence band and near Fermi edge electronic band structure in the quasi-1D compound NaV2O4. In this current study we have acquired the very first high-quality, high-resolution ARPES data from this material. Our data clearly reveal two distinct dispersive bands that cross the Fermi level at different k(F). This is a clear signature that the electronic properties of this material is affected by the presence of a mixed valence state on the different vanadium chains and possibly also the low-temperature magnetic spin order.
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| 7. |
- Sugiyama, J., et al.
(författare)
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Desorption reaction in MgH 2 studied with in situ μ + SR
- 2019
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Ingår i: Sustainable Energy & Fuels. - : Royal Society of Chemistry. - 2398-4902. ; 3:4, s. 956-964
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Tidskriftsartikel (refereegranskat)abstract
- In order to study the mechanism determining the desorption temperature (T d ) of hydrogen storage materials, we have measured positive muon spin rotation and relaxation (μ + SR) in MgH 2 over a wide temperature range including its T d . The pressure in the sample cell due to desorbed H 2 was measured in parallel with the μ + SR measurements under static conditions. Such in situ μ + SR measurements revealed that hydrogen starts to diffuse in MgH 2 well below T d . This indicates the important role of hydrogen diffusion in accelerating the desorption reaction by removing the reaction product, i.e. H 2 , from the reaction system.
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| 8. |
- Borgwardt, L., et al.
(författare)
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Alpha-mannosidosis: characterization of CNS pathology and correlation between CNS pathology and cognitive function
- 2016
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Ingår i: Clinical Genetics. - : Wiley. - 0009-9163. ; 89:4, s. 489-494
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Tidskriftsartikel (refereegranskat)abstract
- Alpha-mannosidosis (AM) (OMIM 248500) is a rare lysosomal storage disease. The understanding of the central nervous system (CNS) pathology is limited. This study is the first describing the CNS pathology and the correlation between the CNS pathology and intellectual disabilities in human AM. Thirty-four patients, aged 6-35 years, with AM were included. Data from 13 healthy controls were included in the analysis of the magnetic resonance spectroscopy (MRS). Measurements of CNS neurodegeneration biomarkers in cerebrospinal fluid (CSF), CSF-oligosaccharides, and performance of cerebral magnetic resonance imaging (MRI) and MRS were carried out. On MRI, 5 of 10 patients had occipital white matter (WM) signal abnormalities, and 6 of 10 patients had age-inappropriate myelination. MRS demonstrated significantly elevated mannose complex in gray matter and WM. We found elevated concentrations of tau-protein, glial fibrillary acidic protein and neurofilament light protein in 97 patients, 74% and 41% of CSF samples, respectively. A negative correlation between CSF-biomarkers and cognitive function and CSF-oligosaccharides and cognitive function was found. The combination of MRS/MRI changes, elevated concentrations of CSF-biomarkers and CSF-oligosaccharides suggests gliosis and reduced myelination, as part of the CNS pathology in AM. Our data demonstrate early neuropathological changes, which may be taken into consideration when planning initiation of treatment.
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| 9. |
- Horio, M., et al.
(författare)
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Two-dimensional type-II Dirac fermions in layered oxides
- 2018
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Ingår i: Nature Communications. - : NATURE PUBLISHING GROUP. - 2041-1723. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Relativistic massless Dirac fermions can be probed with high-energy physics experiments, but appear also as low-energy quasi-particle excitations in electronic band structures. In condensed matter systems, their massless nature can be protected by crystal symmetries. Classification of such symmetry-protected relativistic band degeneracies has been fruitful, although many of the predicted quasi-particles still await their experimental discovery. Here we reveal, using angle-resolved photoemission spectroscopy, the existence of two-dimensional type-II Dirac fermions in the high-temperature superconductor La1.77Sr0.23CuO4. The Dirac point, constituting the crossing of d(x2-y2) and d(z2) bands, is found approximately one electronvolt below the Fermi level (E-F) and is protected by mirror symmetry. If spin-orbit coupling is considered, the Dirac point degeneracy is lifted and the bands acquire a topologically non-trivial character. In certain nickelate systems, band structure calculations suggest that the same type-II Dirac fermions can be realised near EF.
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| 10. |
- Klyushina, E. S., et al.
(författare)
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Investigation of the spin-1 honeycomb antiferromagnet BaNi2V2O8 with easy-plane anisotropy
- 2017
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Ingår i: Physical Review B. - : AMER PHYSICAL SOC. - 2469-9950 .- 2469-9969. ; 96:21
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Tidskriftsartikel (refereegranskat)abstract
- The magnetic properties of the two-dimensional, S = 1 honeycomb antiferromagnet BaNi2V2O8 have been comprehensively studied using dc susceptibility measurements and inelastic neutron scattering techniques. The magnetic excitation spectrum is found to be dispersionless within experimental resolution between the honeycomb layers, while it disperses strongly within the honeycomb plane where it consists of two gapped spin-wave modes. The magnetic excitations are compared to linear spin-wave theory allowing the Hamiltonian to be determined. The first-and second-neighbor magnetic exchange interactions are antiferromagnetic and lie within the ranges 10.90 meV <= J(n) <= 13.35 meV and 0.85 meV <= J(nn) <= 1.65 meV, respectively. The interplane coupling J(out) is four orders of magnitude weaker than the intraplane interactions, confirming the highly two-dimensional magnetic behavior of this compound. The sizes of the energy gaps are used to extract the magnetic anisotropies and reveal substantial easy-plane anisotropy and a very weak in-plane easy-axis anisotropy. Together these results reveal that BaNi2V2O8 is a candidate compound for the investigation of vortex excitations and Berezinsky-Kosterliz-Thouless phenomenon.
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