| 1. |
- Andreasson, Håkan, 1966
(författare)
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Black hole formation from a complete past for the einstein–vlasov system
- 2014
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Ingår i: International conference on Relativity and Gravitation, 2012, Prague, Czech Republic, 25-29 June 2012. - Cham : Springer International Publishing. - 0930-8989 .- 1867-4941. - 9783319067605 ; 157, s. 11-18
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Konferensbidrag (refereegranskat)abstract
- Anatural question in general relativity is to find initial data for the Einstein equations whose past evolution is regular and whose future evolution contains a black hole. In [1] initial data of this kind is constructed for the spherically symmetric Einstein–Vlasov system. One consequence of the result is that there exists a class of initial data for which the ratio of the Hawking mass (Formula presented) (r) and the area radius r is arbitrarily small everywhere, such that a black hole forms in the evolution. This result is analogous to the result [2] for a scalar field. Another consequence is that there exist black hole initial data such that the solutions exist for all Schwarzschild time t ∈ (−∞,∞). In the present article we review the results in [1].
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| 2. |
- Bandyopadhyay, Triparno, et al.
(författare)
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Notes on a Z′
- 2021
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Ingår i: XXIII DAE High Energy Physics Symposium - Select Proceedings. - Singapore : Springer Nature Singapore. - 1867-4941 .- 0930-8989. - 9789813344075 ; 261, s. 175-180
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Konferensbidrag (refereegranskat)abstract
- We reexamine anomaly free U(1) extensions of the standard model in the light of LHC Drell-Yan data, constraints from unitarity, and neutrino-electron scattering to put model-independent bounds in the parameter space populated by MZ′, the Z- Z′ mixing angle (αz ), and the extra U(1) effective gauge coupling (gx′ ). We propose a formalism where any model dependence is absorbed into these three parameters.
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| 3. |
- Cederwall, Martin, 1961
(författare)
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Pure spinor superfields - an overview
- 2014
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Ingår i: Springer Proceedings in Physics. - Cham : Springer International Publishing. - 0930-8989 .- 1867-4941. ; 153, s. 61-93
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Konferensbidrag (refereegranskat)abstract
- Maximally supersymmetric theories do not allow off-shell superspace formulations with traditional superfields containing a finite set of auxiliary fields. It has become clear that off-shell supersymmetric action formulations of such models can be achieved by the introduction of pure spinors. In this talk, an overview of this formalism is given, with emphasis on D=10 super-Yang-Mills theory and D=11 supergravity. This a somewhat expanded version of a talk presented at the workshop "Breaking of supersymmetry and ultraviolet divergences in extended supergravity" (BUDS), Laboratori Nazionali di Frascati, March 25-28, 2013.
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| 4. |
- Ekström, Andreas, 1980
(författare)
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Strong Interactions for Precision Nuclear Physics
- 2020
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Ingår i: Springer Proceedings in Physics. - Cham : Springer International Publishing. - 0930-8989 .- 1867-4941. ; 238, s. 549-558
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Konferensbidrag (refereegranskat)abstract
- One of the key challenges in ab initio nuclear theory is to understand the emergence of nuclear structure from quantum chromodynamics. I will address this challenge and focus on the statistical aspects of uncertainty quantification and parameter estimation in chiral effective field theory.
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| 5. |
- Golub, Mikhail, 1982, et al.
(författare)
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Modelling of elastic wave propagation through damaged interface via effective spring boundary conditions
- 2018
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Ingår i: Springer Proceedings in Physics. - Cham : Springer International Publishing. - 0930-8989 .- 1867-4941. ; 207, s. 375-387
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Konferensbidrag (refereegranskat)abstract
- The present work deals with the application of spring boundary conditions in order to describe elastic wave propagation in composites with damaged interfaces. Dynamic behaviour of the damaged zone is described by means of a distribution of micro-cracks and introduction of spring boundary conditions, where stresses are proportional to the jump in displacement along the damaged interface and the proportionality factor is the distributed spring stiffness. The stiffness in the spring boundary conditions is determined from the equivalence of the transmission coefficients for these two models. As a result, the normal and tangential components of the spring stiffness tensor depend on the concentration of the defects, their typical size and elastic properties of the contacting materials. The three-dimensional problem with elastic wave scattering by a random or periodic distribution of rectangular microcracks is considered, the latter with a boundary integral equation method. The transmission through the damaged interface with random and periodic distribution of rectangular cracks is compared with a good correspondence giving confidence that the models are appropriate.
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| 6. |
- Hansson, Thors Hans, et al.
(författare)
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Effective field theories for topological states of matter
- 2020
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Ingår i: Springer Proceedings in Physics. - Cham : Springer. - 0930-8989 .- 1867-4941. ; 239, s. 1-68
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Tidskriftsartikel (refereegranskat)abstract
- Since the discovery of the quantum Hall effect in the 1980s it has been clear that there exists states of matter characterized by subtle quantum mechanical effects that renders certain properties surprisingly stable against dirt and noise. The theoretical understanding of these topological quantum phases have continued to develop during the last few decades and it has really surged after the discovery of the time-reversal invariant topological insulators. There are many examples of topological phases that have been important for the theoretical understanding of topological states of matter as well as being of great physical relevance. In this chapter we will focus on some examples that we find particularly enlightening and relevant, but we will not make a complete classification. Some of the most important tools for the understanding of topological quantum matter are based on effective field theory methods. We shall employ two different types of effective field theories. The first, which is valid at intermediate length and time-scales, will not capture the physics at microscopic scales. Such theories are the analogs, for topological phases, of the Ginzburg–Landau theories used to describe the usual symmetry breaking non-topological phases. The second type of theories describe the physics on scales where non-topological gapped states would be very boring, namely at distances and times much larger than the correlation length and the time set by the inverse gap. On these scales everything is independent of any distance and the theories will be topological field theories, which do not describe any dynamics in the bulk, but do carry information about topological properties of the excitations, and also about excitations at the boundaries of the system. Finally, we will also study effective response actions. In a strict sense these are not effective theories, since they do not have any dynamical content, but encode the response of the system to external perturbations, typically an electromagnetic field. As we shall see, however, the effective response action for topological states can be used to extract parts of the dynamic theory through a method called functional bosonization.
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| 7. |
- Hernandez, O. J., et al.
(författare)
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A Statistical Analysis of the Nuclear Structure Uncertainties in μD
- 2020
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Ingår i: Springer Proceedings in Physics. - Cham : Springer International Publishing. - 0930-8989 .- 1867-4941. ; 238, s. 833-837
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Konferensbidrag (refereegranskat)abstract
- The charge radius of the deuteron (D), was recently determined to three times the precision compared with previous measurements using the measured Lamb shift in muonic deuterium ((formula presented)D). However, the (formula presented)D value is 5.6 (formula presented) smaller than the world averaged CODATA-2014 value (Pohl R et al. (2016) Science 353:669 [1]). To shed light on this discrepancy we analyze the uncertainties of the nuclear structure calculations of the Lamb shift in (formula presented)D and conclude that nuclear theory uncertainty is not likely to be the source of the discrepancy.
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| 8. |
- Karlsson, Anna, 1987
(författare)
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Loop amplitude diagrams in manifest, maximal supergravity
- 2014
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Ingår i: Springer Proceedings in Physics. - Cham : Springer International Publishing. - 0930-8989 .- 1867-4941.
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Konferensbidrag (refereegranskat)abstract
- The issue of finiteness of maximal supergravity has been subject to research for quite some time. Here, we approach that question through an examination of how to describe amplitude diagrams in D=11 maximal supergravity from a field theory point of view. The strength of the formulation is the presence of manifest supersymmetry through the use of pure spinors. An initial analysis of what the subsequent characteristics turn out to be, partly in lower dimensions through dimensional reduction, gives at hand results that agree with previous work, pointing towards a first divergence for the 7-loop contribution to the 4-point amplitude in four dimensions. The text is mainly based on [arXiv:1212.5175] and may be regarded as an introduction to the main points presented there.
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| 9. |
- Kleinhans, David, 1979, et al.
(författare)
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Synthetic turbulence models for wind turbine applications
- 2010
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Ingår i: Springer Proceedings in Physics. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 0930-8989 .- 1867-4941. ; 131, s. 111-114
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Konferensbidrag (refereegranskat)abstract
- Wind energy converters such as wind turbines permanently work in the atmospheric boundary layer. For the modelling of the dynamics and for the optimisation of design and material of wind turbines synthetic models for atmospheric turbulence are applied already for a long time. The main purpose of these models is to provide fast and efficient methods for numerical simulation of random fields, that show some characteristic features of atmospheric turbulence. Typically they only have a partial connection to the fundamental equations of fluid dynamics. After a short overview summarizing widespread models by Veers and Mann, that are based on the simulation of random fields in the Fourier domain, advanced models for the simulation of velocity fields are discussed.
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| 10. |
- Miliucci, M., et al.
(författare)
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Kaonic Deuterium Precision Measurement at DA Φ NE : The SIDDHARTA-2 Experiment
- 2020
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Ingår i: Recent Progress in Few-Body Physics : Proceedings of the 22nd International Conference on Few-Body Problems in Physics, FB22 2018 - Proceedings of the 22nd International Conference on Few-Body Problems in Physics, FB22 2018. - Cham : Springer International Publishing. - 0930-8989 .- 1867-4941. - 9783030323561 - 9783030323578 ; 238, s. 965-969
-
Bokkapitel (refereegranskat)abstract
- Light kaonic atoms spectroscopy offers the unique opportunity to perform experiments equivalent to scattering at vanishing relative energies. This allows the determination of the antikaon-nucleus interaction at threshold, without the need of extrapolation to zero energy, as in the case of scattering experiments. In this framework, the SIDDHARTA-2 collaboration aims to perform the first measurement of kaonic deuterium transition to the fundamental level, which is mandatory to extract the isospin dependent antikaon—nucleon scattering lengths. The experiment will be carried out at the DA(formula presented)NE collider of LNF-INFN in 2019–2020.
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| 11. |
- Minelli, Guglielmo, 1988, et al.
(författare)
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Numerical Investigation of the Actuated Flow on a Bluff Body
- 2016
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Ingår i: Springer Proceedings in Physics. - Cham : Springer International Publishing. - 0930-8989 .- 1867-4941. ; 185, s. 295-302
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Konferensbidrag (refereegranskat)abstract
- Large Eddy Simulations (LES) are conducted to study the Active Flow Control (AFC) of the separation of the boundary layer on a rounded leading edge frontstep. This bluff body imitates the flow around a section of a simplified truck cabin and focuses on the separation arising at the front rounded corner, the so called A-pillar. The LES data show the connection between the actuation and drag reduction. The actuated and unactuated flows are analysed using modal decomposition and frequency analysis. Different configurations are tested and a strong influence of the actuation on both drag reduction and separation mechanism was observed. Relevant results, in terms of drag coefficient and recirculation bubble reduction, are achieved when the flow is actuated. LES shows an increased unsteadiness in the flow, introduced by the actuation. An analysis that investigates the connection between actuation and induced unsteadiness is presented.
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| 12. |
- Mirzaei, Maryam, 1982, et al.
(författare)
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Large Eddy Simulations of Flow Around Two Generic Vehicles in a Platoon
- 2016
-
Ingår i: Springer Proceedings in Physics. - Cham : Springer International Publishing. - 0930-8989 .- 1867-4941. - 9783319306025 ; 185, s. 283-288
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Konferensbidrag (refereegranskat)abstract
- A detailed analysis of the effect of inter-vehicle distance on the flow structure of a two-model platoon is presented. Simulations are made for two Ahmed bodies with a slant angle of 25 degrees and for three inter-vehicle distances, d/L = 0.3, 0.5 and 1. The Reynolds number based on the body height was 30000. A drag increase was observed for the follower with d/L = 0.5, compared to the drag value of a single body in isolation. To explain the underlying reasons for the increase in drag, various instantaneous and time-averaged plots are presented and compared for different distances, and a significant change in flow structure was found in flows between the set-ups with d/L = 0.5 and d/L = 1.
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| 13. |
- Mirzaei, Maryam, 1982, et al.
(författare)
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Numerical Study of Aerodynamic Interactions in a Homogeneous Multi-vehicle Formation
- 2016
-
Ingår i: Springer Proceedings in Physics. - Cham : Springer International Publishing. - 0930-8989 .- 1867-4941. - 9783319306025 ; 185, s. 289-294
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Konferensbidrag (refereegranskat)abstract
- An accurate and affordable method to study the flow features associated with vehicles in a homogeneous platooning is presented in this paper. It was found that only one pitch of a long-line periodic platoon would provide a sufficiently accurate observation of the flow interaction in the inter-vehicle region of the vehicles offering a significant reduction of the computational effort. The simulations of flow at Reynolds number of 30000 are made for a periodic platoon including slanted-back Ahmed bodies with a slant angle of 25 degrees and for four inter-vehicle distances, d/L = 0.1, 0.3, 0.5 and 1.
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| 14. |
- Richter, Steffen, et al.
(författare)
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Spectral and polarization properties of VUV-mirrors for experiments at a HHG beamline
- 2020
-
Ingår i: Springer Proceedings in Physics. - Cham : Springer International Publishing. - 0930-8989 .- 1867-4941. ; 241, s. 175-179, s. 175-179
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Konferensbidrag (refereegranskat)abstract
- For polarization-resolved reflection experiments such as ellipsometry, not only is high reflectivity in a wide spectral range required for mirrors but also the quality of their polarization response is important. Furthermore, for VUV ellipsometry, optimal angles of incidence at the sample are between 45° and 60° with respect to the surface normal. In the best case, a setup should even allow variable angles. This requires reflective optics working at non-grazing incidence. In this theoretical study, a selection of potentially relevant materials and mirror designs for broadband use in the VUV is investigated. Based on the available tabulated databases of optical constants, we performed transfer-matrix calculations to obtain reflectance as well as polarization-response spectra in the desired VUV range up to 50 eV. From the variety of materials, we discuss metals that are otherwise commonly used at grazing incidence, Si, SiC, and as representatives for coating layers MgF2, SiO2, and Al2O3. While SiC is most universal, Si with only native oxide layer performs well especially below 25 eV. Aluminum has good properties but oxide layers are very detrimental, as protective coatings are in general.
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| 15. |
- Sahoo, Baidyanath, et al.
(författare)
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Simulation Studies of R2(Δ η, Δ ϕ) and P2(Δ η, Δ ϕ) Correlation Functions in pp Collisions with the PYTHIA and HERWIG Models
- 2022
-
Ingår i: Proceedings of the 24th DAE-BRNS High Energy Physics Symposium, 2020. - Singapore : Springer Nature Singapore. - 0930-8989 .- 1867-4941. - 9789811923531 ; 277, s. 349-352
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Konferensbidrag (refereegranskat)abstract
- We presented a study of charge-independent (CI) and charge-dependent (CD) two-particle differential number correlation functions R2 and transverse momentum correlation functions P2 in pp collisions at s=2.76 TeV with the PYTHIA and HERWIG models.Calculations were presented for unidentified hadrons in three pT ranges 0.2 < pT≤ 2.0 GeV/c, 2.0 < pT≤ 5.0 GeV/c, and 5.0 < pT≤ 30.0 GeV/c.PYTHIA and HERWIG both qualitatively reproduce the near-side peak and away-side ridge correlation features reported by experiments.At low pT, both models produce narrower near-side peaks in P2 correlations than in R2 as reported by the ALICE collaboration in p–Pb and Pb–Pb collisions.This suggests that the narrower shape of the P2 near-side peak is largely determined by the pT dependent angular ordering of hadrons produced in jets.Both PYTHIA and HERWIG predict widths that decrease with increasing pT.Widths extracted for P2 correlators are typically significantly narrower than those of the R2 counterparts [1].
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| 16. |
- Seres, J., et al.
(författare)
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Attosecond dynamics of parametric amplification at 11 nm
- 2016
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Ingår i: X-Ray Lasers 2014 - Proceedings of the 14th International Conference on X-Ray Lasers. - Cham : Springer International Publishing. - 1867-4941 .- 0930-8989. - 9783319195209 ; 169, s. 173-178
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Konferensbidrag (refereegranskat)abstract
- X-ray parametric amplification is a high order parametric process with the capability to amplify ultrashort laser pulses with broad spectrum ranging from the extreme ultraviolet to the soft x-ray. In this contribution, the dynamics of this broadband amplification schema is studied with sub-20-as temporal resolution by seeding the amplifier with a train of 200-as-long pulses at 11 nm central wavelength.
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| 17. |
- Sukhareva, O. M., et al.
(författare)
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Validity of Quasi-classical Approaches to True Three-Body Decays
- 2020
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Ingår i: Springer Proceedings in Physics. - Cham : Springer International Publishing. - 0930-8989 .- 1867-4941. ; 238, s. 283-286
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Konferensbidrag (refereegranskat)abstract
- Within the hyperspherical harmonics (HH) method the three-body problem is reduced to a motion of one effective particle in a “strongly deformed” field, which is described in the coupled-channel formalism. This method is well suited to studies of so-called true three-body decays. The reduction of the hyperspherical equations set to a single-channel approximation provides the basis of standard quasi-classical (QC) expression for width evaluation. We demonstrate that by itself the quasi-classical approach is quite precise in application to typical three-body effective potentials. However, the reduction to a single channel leads to a significant overestimation of the width.
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| 18. |
- Tavani, Francesco, et al.
(författare)
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Insights into the Structure of Reaction Intermediates Through Coupled X-ray Absorption/UV-Vis Spectroscopy
- 2021
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Ingår i: Springer Proceedings in Physics. - Cham : Springer International Publishing. - 0930-8989 .- 1867-4941. ; 220, s. 141-154
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Konferensbidrag (refereegranskat)abstract
- In this work, we propose a method for the structural characterization of chemical reaction intermediates. It allows one to analyze time-resolved coupled energy dispersive X-ray absorption spectroscopy (EDXAS) and UV-Vis reaction data through a matricial approach. Concentration profiles for the reaction key species are derived from the UV-Vis data and are used as mathematical constraints to extract their associated X-ray absorption near edge structure (XANES) spectra. The obtained XANES spectra are then quantitatively characterized by full multiple scattering (MS) calculations. We demonstrate the capabilities of this approach by applying it over a series of coupled EDXAS/UV-Vis spectra acquired in the reaction between FeII (tris(2-pyridylmethyl)amine) ([FeII(TPA)(CH3CN)2]2+ ) and H2O2. As a result, structural information for the elusive reaction key intermediate [ FeIII (TPA)(OOH)(X)]2 + is derived and it is suggested that X = CH3CN in opposition to X = H2O.
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| 19. |
- Yang, Zaihong, et al.
(författare)
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Study of Multi-neutron Systems with SAMURAI Spectrometer
- 2020
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Ingår i: Recent Progress in Few-Body Physics, FB22 201. - Cham : Springer International Publishing. - 0930-8989 .- 1867-4941. - 9783030323561 - 9783030323578 ; 238, s. 529-534
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Bokkapitel (refereegranskat)abstract
- The tetraneutron has been drawing the attention of the nuclear physics community for decades, but a firm conclusion on its existence and properties is still far from being reached despite many experimental and theoretical efforts. New measurements have recently been performed at RIBF with the SAMURAI spectrometer by applying complementary reaction probes, which will help to pin down the properties of this four-neutron system.
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| 20. |
- yilmas, I, 1980, et al.
(författare)
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Application and Comparison of Two Different DNS Algorithms for Simulating Transition to Turbulence in Taylor-Green Vortex Flow
- 2012
-
Ingår i: Springer Proceedings in Physics. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 0930-8989 .- 1867-4941. ; 141, s. 91-94
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Konferensbidrag (refereegranskat)abstract
- An all-Mach number, fully implicit, non-dissipative DNS algorithm and an incompressible, dissipative DNS algorithm were applied for simulating transition to turbulence in TGV flow to assess their behavior for this flow regime. The all-Mach number solver was developed and parallelized. A method was also adopted to remove oscillating pressure corrections in time. In order to compare the behavior of the algorithms, various flow diagnostics were calculated. The results were also compared to results given in the literature. The development of the flow and the peak structures show some differences due to different dissipative and energy conserving properties of the algorithms. However the physics of TGV flow are well captured by both, even though the grid is not fully resolved.
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| 21. |
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| 22. |
- Bayat, A., et al.
(författare)
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Quantum thermodynamics at impurity quantum phase transitions
- 2020
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Ingår i: Springer Proceedings in Physics. - Cham : Springer International Publishing. - 0930-8989. ; 239, s. 361-373
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Tidskriftsartikel (refereegranskat)abstract
- The study of quantum thermodynamics, i.e. equilibrium and non-equilibrium thermodynamics of quantum systems, has been applied to various many-body problems, including quantum phase transitions. An important question is whether out-of-equilibrium quantities from this emerging field, such as fluctuations of work, exhibit scaling after a sudden quench. In particular, it is very interesting to explore this problem in impurity models where the lack of an obvious symmetry breaking at criticality makes it very challenging to characterize. Here, by considering a spin emulation of the two impurity Kondo model and performing density matrix renormalization group computations, we establish that the irreversible work produced in a quench exhibits finite-size scaling at quantum criticality. Our approach predicts the equilibrium critical exponents for the crossover length and the order parameter of the model, and, moreover, implies a new exponent for the rescaled irreversible work. © Springer Nature Switzerland AG 2020.
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| 23. |
- Bose, S., et al.
(författare)
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Entanglement content of many-body states via concurrence, negativity and schmidt gap
- 2020
-
Ingår i: Springer Proceedings in Physics. - Cham : Springer International Publishing. - 0930-8989. ; 239, s. 91-107
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Tidskriftsartikel (refereegranskat)abstract
- Quantum entanglement is nearly ubiquitous in equilibrium and non-equilibrium many-body states. Although it has been largely studied through the von Neumann entropy of a subsystem, which quantifies the entanglement between two complementary parts of a many-body system, this is not necessarily the only way. Here we review how some other measures can be fruitful in characterizing the entanglement content of many-body states. For example, we can look at the entangement between two individual spins through the concurrence or between two non-complementary, but in principle large, parts of a many-body system through the negativity. Alternatively, a quantity inspired through entanglement studies, but not itself a measure of entanglement, namely the Schmidt gap, can be effective as an order parameter for phase transitions in which only the entanglement structure of a many-body system changes. We exemplify using equilibrium states of short-range and impurity models and their quantum phase transitions. © Springer Nature Switzerland AG 2020.
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| 24. |
- Brzek, Brian, et al.
(författare)
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Near Wall Measurements in Rough Surface Turbulent Boundary Layers
- 2007
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Ingår i: J.M.L.M. Palma and A. Silva Lopes (Eds.), "Advances in Turbulence XI", Proceedings of the 11th EUROMECH European Turbulence Conference, June 25-28, 2007, Porto, Portugal. Springer proceedings in physics 117.. - 0930-8989. - 9783540726036 ; , s. 295-297
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Konferensbidrag (refereegranskat)
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| 25. |
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| 26. |
- Duwig, Christophe, et al.
(författare)
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Large Scale Dynamics of a Jet in a Counter Flow
- 2009
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Ingår i: Advances in Turbulence XII - Proceedings of the 12th Euromech European Turbulence Conference. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 0930-8989. ; 132, s. 321-324
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Konferensbidrag (refereegranskat)
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| 27. |
- Grönlund, Rasmus, et al.
(författare)
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Fluorescence lidar multispectral imaging for diagnosis of historical monuments - Övedskloster, a Swedish case study
- 2007
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Ingår i: Springer Proceedings in Physics. - 0930-8989. ; 116, s. 583-591
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Konferensbidrag (refereegranskat)abstract
- A fluorescence lidar measurement has been performed on the castle Övedskloster in Sweden. A mobile system from the Lund University was placed at ~40 m distance from the sandstone façade. The lidar system, which uses a frequency-tripled Nd:YAG laser with a 355-nm pulsed beam, induces fluorescence in each target point. Areas were studied by using whisk-broom scans. The possibility of detecting biodeteriogens on the surface and characterization of materials was confirmed. The method can be a tool for conservation planning and status control of the architectural heritage where fluorescence light can point out features that are not normally visible under natural illumination.
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| 28. |
- Gustafsson, Anders, et al.
(författare)
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Cathodoluminescence Studies of AlGaAs/GaAs Core-Shell Nanowires
- 2005
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Ingår i: Springer Proceedings in Physics. - 0930-8989. ; 107, s. 463-466
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Konferensbidrag (refereegranskat)abstract
- We have studied nanowires with a GaAs core, covered by an AlGaAs shell, using low temperature cathodoluminescence. The main emission from the core is due carbon acceptors, though we observe a weak emission from excitons. A general observation is that the emission is much stronger from the top half of the nanowire. This emission is also more well-defined. The AlGaAs shell emission varies in emission energy and spatial origin in an irregular fashion.
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| 29. |
- Karlsson, L. S., et al.
(författare)
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Structural Characterisation of GaP <111 > B Nanowires by HRTEM
- 2008
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Ingår i: Microscopy of Semiconducting Material 2007. - 0930-8989. - 9781402086144 ; 120, s. 229-232
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Konferensbidrag (refereegranskat)abstract
- GaP < 111 > B nanowires are dominated by (111) twins orthogonal to the growth direction and show well-developed {111} side-facets. Based on this, a 3D-model has been constructed with a cross-section of an octahedron used as a building block. The twins can be of ortho- or para type i.e. by 60 degrees about the growth axis or 180 degrees in the twin plane. The segment thickness variation follows an exponential distribution with a clear dependence oil growth ternperature. Multislice simulations show different features of the twin types that are useful for further characterisation.
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| 30. |
- Krajnovic, Sinisa, 1970, et al.
(författare)
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Numerical Simulation of the Flow around a Tall Finite Cylinder Using LES and PANS
- 2010
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Ingår i: Progress in Turbulence III, Springer Proceedings in Physics. Proceedings of the iTi Conference in Turbulence 2008. Bertinoro, ITALY, OCT 12-15.. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 0930-8989. - 9783642022241 ; 131, s. 115-118
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Konferensbidrag (refereegranskat)abstract
- Two unsteady numerical techniques, LES and PANS, with difference computer requirements, were used for prediction of the flow around a tall finite cylinder. The well resolved LES was found to predict the flow in agreement with previous experimental observations, while PANS was found to suffer from the combination of k - epsilon model in conjuction with wall function close to the wall of the cylinder and too coarse resolution.
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| 31. |
- Rohringer, N., et al.
(författare)
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Stimulated X-Ray Raman Scattering with Free-Electron Laser Sources
- 2016
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Ingår i: X-Ray Lasers 2014. - Cham : Springer. - 0930-8989. - 9783319195216 - 9783319195209 ; , s. 201-207
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Bokkapitel (refereegranskat)abstract
- Stimulated electronic x-ray Raman scattering is the building block for several proposed x-ray pump probe techniques, that would allow the study of electron dynamics at unprecedented timescales.We present high spectral resolution data on stimulated electronic x-ray Raman scattering in a gas sample of neon using a self-amplified spontaneous emission x-ray free-electron laser. Despite the limited spectral coherence and broad bandwidth of these sources, high-resolution spectra can be obtained by statistical methods, opening the path to coherent stimulated x-ray Raman spectroscopy. An extension of these ideas to molecules and the results of a recent experiment in CO are discussed.
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| 32. |
- Schuette, B., et al.
(författare)
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Recombination-Induced Autoionization Process in Rare-Gas Clusters
- 2015
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Ingår i: Ultrafast Phenomena XIX. - Cham : Springer International Publishing. - 0930-8989. ; 162, s. 56-59
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Konferensbidrag (refereegranskat)abstract
- We investigate electron-ion recombination to excited states in atomic clusters exposed to intense NIR and XUV pulses, which leads to a yet undiscovered autoionization mechanism as a consequence of multiple recombination processes.
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| 33. |
- Wikberg, J. M., et al.
(författare)
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Evolving Magnetization Dynamics in Mn3-xGa
- 2015
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Ingår i: Springer Proceedings in Physics. - Cham : Springer International Publishing. - 0930-8989. ; 159, s. 23-25, s. 23-25
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Konferensbidrag (refereegranskat)abstract
- Magnetic materials with high magnetic coercivity (Hc), magnetic anisotropy (Ku) and low Gilbert damping (α) are of great importance for future spintronics devices. For instance, for spin-transfer-torque (STT) memory devices low α and high Ku are desired. Such a combination of material properties includes a built in contradiction since both Ku and α are dependent on the spin-orbit interaction (SO); a high Ku material is expected to have a high α. However, recent experimental investigations of Mn3-xGa, a material exhibiting high Curie temperature (Tc) > 700 K and (out-of-plane) perpendicular anisotropy, have shown that such a contradictorily low α and high Ku material exists.
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