SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "L773:1367 2630 OR L773:1367 2630 "

Sökning: L773:1367 2630 OR L773:1367 2630

  • Resultat 1-10 av 346
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Carlström, Stefanos, et al. (författare)
  • Spatially and spectrally resolved quantum path interference with chirped driving pulses
  • 2016
  • Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 18:12
  • Tidskriftsartikel (refereegranskat)abstract
    • We measure spectrally and spatially resolved high-order harmonics generated in argon using chirped multi-cycle laser pulses. Using a stable, high-repetition rate laser we observe detailed interference structures in the far-field. The structures are of two kinds; off-axis interference from the long trajectory only and on-axis interference including the short and long trajectories. The former is readily visible in the far-field spectrum, modulating both the spectral and spatial profile. To access the latter, we vary the chirp of the fundamental, imparting different phases on the different trajectories, thereby changing their relative phase. Using this method together with an analytical model, we are able to explain the on-axis behaviour and access the dipole phase parameters for the short (${\alpha }_{{\rm{s}}}$) and long (${\alpha }_{{\rm{l}}}$) trajectories. The extracted results compare very well with phase parameters calculated by solving the time-dependent Schrödinger equation. Going beyond the analytical model, we are also able to successfully reproduce the off-axis interference structure.
  •  
2.
  • Kanski, Janusz, 1946, et al. (författare)
  • Electronic structure of (Ga,Mn)As revisited
  • 2017
  • Ingår i: New Journal of Physics. - : Institute of Physics (IOP). - 1367-2630. ; 19:2, s. 1-8
  • Tidskriftsartikel (refereegranskat)abstract
    • The detailed nature of electronic states mediating ferromagnetic coupling in dilute magnetic semiconductors, specifically (Ga,Mn)As, has been an issue of long debate. Two confronting models have been discussed emphasizing host band vs. impurity band carriers. Using angle resolved photoemission we show that the electronic structure of the (Ga,Mn)As system is significantly modified from that of GaAs throughout the valence band. Close to the Fermi energy, the presence of Mn induces a strong mixing of the bulk bands of GaAs, which results in the appearance of a highly dispersive band in the gap region of GaAs.For Mn concentrations above 1% the band reaches the Fermi level, and can thus host the delocalized holes needed for ferromagnetic coupling. Overall, our data provide a firm evidence of delocalized carriers belonging to the modified host valence band.
  •  
3.
  • Konopik, Michael, et al. (författare)
  • Solving the subset sum problem with a nonideal biological computer
  • 2021
  • Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 23:9
  • Tidskriftsartikel (refereegranskat)abstract
    • We consider the solution of the subset sum problem based on a parallel computer consisting of self-propelled biological agents moving in a nanostructured network that encodes the computing task in its geometry. We develop an approximate analytical method to analyze the effects of small errors in the nonideal junctions composing the computing network by using a Gaussian confidence interval approximation of the multinomial distribution. We concretely evaluate the probability distribution for error-induced paths and determine the minimal number of agents required to obtain a proper solution. We finally validate our theoretical results with exact numerical simulations of the subset sum problem for different set sizes and error probabilities, and discuss the scalability of the nonideal problem using realistic experimental error probabilities.
  •  
4.
  • Small, Lara S.R., et al. (författare)
  • The bar-hinge motor : A synthetic protein design exploiting conformational switching to achieve directional motility
  • 2019
  • Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 21:1
  • Tidskriftsartikel (refereegranskat)abstract
    • One challenge to synthetic biology is to design functional machines from natural building blocks, from individual amino acids up to larger motifs such as the coiled coil. Here we investigate a novel bipedal motor concept, the Bar-Hinge Motor (BHM), a peptide-based motor capable of executing directed motion via externally controlled conformational switching between a straight bar and a V-shaped hinged form. Incorporating ligand-regulated binding to a DNA track and periodic control of ligand supply makes the BHM an example of a 'clocked walker'. Here, we employ a coarse-grained computational model for the BHM to assess the feasibility of a proposed experimental realization, with conformational switching regulated through the photoisomerization of peptide-bound azobenzene molecules. The results of numerical simulations using the model show that the incorporation of this conformational switch is necessary for the BHM to execute directional, rather than random, motion on a one-dimensional track. The power-stroke-driven directed motion is seen in the model even under conditions that underestimate the level of control we expect to be able to produce in the experimental realisation, demonstrating that this type of design should be an excellent vehicle for exploring the physics behind protein motion. By investigating its force-dependent dynamics, we show that the BHM is capable of directional motion against an applied load, even in the more relaxed conformational switching regimes. Thus, BHM appears to be an excellent candidate for a motor design incorporating a power stroke, enabling us to explore the ability of switchable coiled-coil designs to deliver power strokes within synthetic biology.
  •  
5.
  • Morrison, S, et al. (författare)
  • Physical replicas and the Bose glass in cold atomic gases
  • 2008
  • Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 10:7
  • Tidskriftsartikel (refereegranskat)abstract
    • We study cold atomic gases in a disorder potential and analyse the correlations between different systems subjected to the same disorder landscape. Such independent copies with the same disorder landscape are known as replicas. While, in general, these are not accessible experimentally in condensed matter systems, they can be realized using standard tools for controlling cold atomic gases in an optical lattice. Of special interest is the overlap function which represents a natural order parameter for disordered systems and is a correlation function between the atoms of two independent replicas with the same disorder. We demonstrate an efficient measurement scheme for the determination of this disorder-induced correlation function. As an application, we focus on the disordered Bose–Hubbard model and determine the overlap function within the perturbation theory and a numerical analysis. We find that the measurement of the overlap function allows for the identification of the Bose-glass phase in certain parameter regimes.
  •  
6.
  • Alegret, Joan, 1977, et al. (författare)
  • Green's tensor calculations of plasmon resonances of single holes and hole pairs in thin gold films
  • 2008
  • Ingår i: New Journal of Physics. - Bristol, UK : IOP Publishing. - 1367-2630. ; 10, s. 13-
  • Tidskriftsartikel (refereegranskat)abstract
    • We present numerical calculations of the plasmon properties of single-hole and hole-pair structures in optically thin gold films obtained with the Green's tensor formalism for stratified media. The method can be used to obtain the optical properties of a given hole system, without problems associated with the truncation of the infinite metal film. The calculations are compared with previously published experimental data and an excellent agreement is found. In particular, the calculations are shown to reproduce the evolution of the hole plasmon resonance spectrum as a function of hole diameter, film thickness and hole separation.
  •  
7.
  • Aurand, Bastian, et al. (författare)
  • Radiation pressure-assisted acceleration of ions using multi-component foils in high-intensity laser-matter interactions
  • 2013
  • Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 15
  • Tidskriftsartikel (refereegranskat)abstract
    • Experimental results on the acceleration of protons and carbon ions from ultra-thin polymer foils at intensities of up to 6x10(19)Wcm(-2) are presented revealing quasi-monoenergetic spectral characteristics for different ion species at the same time. For carbon ions and protons, a linear correlation between the cutoff energy and the peak energy is observed when the laser intensity is increased. Particle-in-cell simulations supporting the experimental results imply an ion acceleration mechanism driven by the radiation pressure as predicted for multi-component foils at these intensities.
  •  
8.
  • Favre-Nicolin, V., et al. (författare)
  • Analysis of strain and stacking faults in single nanowires using Bragg coherent diffraction imaging
  • 2010
  • Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 12
  • Tidskriftsartikel (refereegranskat)abstract
    • Coherent diffraction imaging (CDI) on Bragg reflections is a promising technique for the study of three-dimensional (3D) composition and strain fields in nanostructures, which can be recovered directly from the coherent diffraction data recorded on single objects. In this paper, we report results obtained for single homogeneous and heterogeneous nanowires with a diameter smaller than 100 nm, for which we used CDI to retrieve information about deformation and faults existing in these wires. We also discuss the influence of stacking faults, which can create artefacts during the reconstruction of the nanowire shape and deformation.
  •  
9.
  • Foerster, Heidi, et al. (författare)
  • Current-voltage correlations in interferometers
  • 2007
  • Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 9
  • Tidskriftsartikel (refereegranskat)abstract
    • We investigate correlations of current at contacts and voltage fluctuations at voltage probes coupled to interferometers. The results are compared with correlations of current and occupation number fluctuations at dephasing probes. We use a quantum Langevin approach for the average quantities and their fluctuations. For higher order correlations we develop a stochastic path integral approach and find the generating functions of voltage or occupation number fluctuations. We also derive a generating function for the joint distribution of voltage or occupation number at the probe and current fluctuations at a terminal of a conductor. For energy independent scattering we found earlier that the generating function of current cumulants in interferometers with a one-channel dephasing or voltage probe are identical. Nevertheless, the distribution function for voltage and the distribution function for occupation number fluctuations differ, the latter being broader than that of the former in all examples considered here.
  •  
10.
  • Helsing, Johan, et al. (författare)
  • Spectral super-resolution in metamaterial composites
  • 2011
  • Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 13:11
  • Tidskriftsartikel (refereegranskat)abstract
    • We investigate the optical properties of periodic composites containing metamaterial inclusions in a normal material matrix. We consider the case when these inclusions have sharp corners and, following Hetherington and Thorpe, use analytic results to argue that it is then possible to deduce the shape of the corner (its included angle) by measurements of the absorptance of such composites when the scale size of the inclusions and period cell is much finer than the wavelength. These analytic arguments are supported by highly accurate numerical results for the effective permittivity function of such composites as a function of the permittivity ratio of inclusions to the matrix. The results show that this function has a continuous spectral component with limits independent of the area fraction of inclusions, and with the same limits for both square and staggered square arrays. For staggered arrays where the squares are almost touching, the absorption spectrum is an extremely sensitive probe of the inclusion separation distance and acts like a Vernier scale.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-10 av 346
Typ av publikation
tidskriftsartikel (344)
forskningsöversikt (2)
Typ av innehåll
refereegranskat (339)
övrigt vetenskapligt/konstnärligt (7)
Författare/redaktör
Björk, Gunnar (6)
Abbott, B. (6)
Abdallah, J (6)
Abdinov, O (6)
Zwalinski, L. (6)
Doglioni, Caterina (5)
visa fler...
Aben, R. (5)
Aad, G (4)
Ekelöf, Tord (4)
Ferrari, Arnaud (4)
Gregersen, K. (4)
Pelikan, Daniel (4)
Abi, B. (4)
Abramowicz, H. (4)
Abreu, H. (4)
Adams, D. L. (4)
Adelman, J. (4)
Adomeit, S. (4)
Adye, T. (4)
Agustoni, M. (4)
Aielli, G. (4)
Akimoto, G. (4)
Akimov, A. V. (4)
Albert, J. (4)
Albrand, S. (4)
Aleksa, M. (4)
Aleksandrov, I. N. (4)
Alexander, G. (4)
Alexandre, G. (4)
Alexopoulos, T. (4)
Alhroob, M. (4)
Alimonti, G. (4)
Alison, J. (4)
Allport, P. P. (4)
Almond, J. (4)
Aloisio, A. (4)
Alonso, F. (4)
Altheimer, A. (4)
Alviggi, M. G. (4)
Amako, K. (4)
Amelung, C. (4)
Amorim, A. (4)
Amram, N. (4)
Anastopoulos, C. (4)
Ancu, L. S. (4)
Andari, N. (4)
Andeen, T. (4)
Anders, G. (4)
Anderson, K. J. (4)
Andreazza, A. (4)
visa färre...
Lärosäte
Lunds universitet (81)
Kungliga Tekniska Högskolan (65)
Stockholms universitet (58)
Chalmers tekniska högskola (51)
Uppsala universitet (43)
Umeå universitet (30)
visa fler...
Linköpings universitet (30)
Göteborgs universitet (27)
Linnéuniversitetet (9)
Luleå tekniska universitet (5)
Karlstads universitet (5)
Örebro universitet (4)
Karolinska Institutet (3)
Högskolan i Skövde (1)
RISE (1)
visa färre...
Språk
Engelska (346)
Forskningsämne (UKÄ/SCB)
Naturvetenskap (301)
Teknik (34)
Samhällsvetenskap (1)

År

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy