The Experts below are selected from a list of 43134 Experts worldwide ranked by ideXlab platform
Päivi Törmä - One of the best experts on this subject based on the ideXlab platform.
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Collision of one dimensional (1d) spin polarized Fermi gases in an optical lattice
European Physical Journal D, 2011Co-Authors: J. Kajala, Francesco Massel, Päivi TörmäAbstract:In this work we analyze the dynamical behavior of the collision between two clouds of fermionic atoms with opposite spin polarization. By means of the time-evolving block decimation (TEBD) numerical method, we simulate the collision of two One-Dimensional clouds in a lattice. There is a symmetry in the collision behaviour between the attractive and repulsive interactions. We analyze the pair formation dynamics in the collision region, providing a quantitative analysis of the pair formation mechanism in terms of a simple two-site model.
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Fermi-polaron-like effects in a One-Dimensional (1d) optical lattice
New Journal of Physics, 2010Co-Authors: Markku J Leskinen, O. H.t. Nummi, Francesco Massel, Päivi TörmäAbstract:We study a highly imbalanced Fermi gas in a One-Dimensional (1d) optical lattice from the polaronic\r point of view. The time-evolving block decimation algorithm is used to calculate the ground state\r and dynamics of the system. We find polaronic behaviour qualitatively similar to that in the recent\r experiment by Schirotzek et al (2009 Phys. Rev. Lett. 102 230402), where radio-frequency (rf)\r spectroscopy was used to observe polarons in 3D space. In the weakly interacting limit, our exact\r results are in excellent agreement with a polaron ansatz, and in the strongly interacting limit, the\r results match with an approximative solution of the Bethe ansatz (BA), suggesting crossover from a\r quasiparticle to a charge-density excitation regime.
Vladislav Sorokin - One of the best experts on this subject based on the ideXlab platform.
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Longitudinal wave propagation in a One-Dimensional quasi-periodic waveguide
Proceedings of The Royal Society A: Mathematical Physical and Engineering Sciences, 2019Co-Authors: Vladislav SorokinAbstract:The paper deals with the analysis of wave propagation in a general One-Dimensional (1d) non-uniform waveguide featuring multiple modulations of parameters with different, arbitrarily related, spati...
Sebahattin Tüzemen - One of the best experts on this subject based on the ideXlab platform.
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One-Dimensional (1d) ZnO Nanowires Dye Sensitized Solar Cell
Journal of Nanoscience and Nanotechnology, 2013Co-Authors: Bayram Kilic, Lianzhou Wang, Orhan Ozdemir, M.g. Lu, Sebahattin TüzemenAbstract:High ordered One-Dimensional (1d) Zinc oxide (ZnO) nanowires were grown on FTO substrate by using the hydrothermal method. Nanowires structures were used as the wide band-gap semiconducting photo-electrode in dye sensitized solar cell (DSSCs). Solar cell made from ZnO nanowire at 50 nm radius and several tens micron lengths showed high solar conversion efficiency (eta) of 2.1% and incident photon current efficiency (IPCE) 35% using nanowire/N719 dye/I-/I-3(-) electrolyte. We also compared Ru N719 dye and N3 dye on ZnO nanowire against each other in respect to solar conversion efficiency and IPCE measurements. In the case of the N3 dye on ZnO nanowire conversion efficiency (eta) of 1.32% and IPCE 23% were obtained under an illumination of 100 mW/cm(2). It was found that the performance of the Ru N719 dyes was better than about 50% that of the N3 dye in ZnO nanowire dye-sensitized solar cells.
P.l. Sarojini - One of the best experts on this subject based on the ideXlab platform.
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Light trapping mechanism in One-Dimensional (1d) photonic crystals for silicon-based solar cells
Journal of Electromagnetic Waves and Applications, 2012Co-Authors: R.s. Dubey, P.l. SarojiniAbstract:In the present paper, the light trapping mechanism of One-Dimensional (1d) photonic crystal of uniform symmetry for TE polarization is studied. The analysis of the forbidden bands, reflectivity, and group velocity is presented which are interdependent parameters and important to tune the desired optical properties. It is observed that the group velocity is the vanishing factor within the forbidden bands due to the increased optical path length of trapped photons. For solar cells, the use of 1d structure as bottom layer assures the prevention of electron and hole pair recombination for a longer time due to optical delay. We have compared the reflectivity of prepared multilayer (1d) structure of porous silicon with simulated one and important results are presented.
Bodh Raj Mehta - One of the best experts on this subject based on the ideXlab platform.
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Identification and origin of visible transitions in one dimensional (1d) ZnO nanostructures: Excitation wavelength and morphology dependence study
Journal of Luminescence, 2017Co-Authors: Arpit Baral, Manika Khanuja, S. S. Islam, Rishabh Sharma, Bodh Raj MehtaAbstract:Abstract In this present work, one dimensional (1d) ZnO nanostructures were synthesized by mechanical assisted thermal decomposition process. The samples were characterized by transmission electron microscopy (TEM) for morphology, high-resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) for structural characterization. Photoluminescence (PL) and Photoluminescence spectra evolution was studied as a function of (i) excitation wavelength (λ Ex: 310–370 nm) and (ii) morphology (nanoneedles and nanorods). PL spectra were observed to be highly asymmetric with strong dependence on excitation wavelength (λ Ex ). PL spectra categorized into two types as a function of excitation wavelength (λ Ex ): I. λ Ex ≤345 nm and II. λ Ex ≥350 nm. The PL spectra were deconvoluted into multiple Gaussian components for each excitation wavelength. The position of each component is a signature of its origin and corresponds to specific visible transition. The transition involving origin from conduction band (CB) are absent for excitation wavelength λ Ex ≥350 nm. The tunable photoresponse is achieved in 1d ZnO nanostructures by varying (i) excitation wavelength and (ii) morphology: nanoneedles to nanorods. PL intensity increases as aspect ratio decrease from nanoneedles to nanorods morphology. This is attributed to non-radiative quenching by near surface defects.
