We present a complex multicon figurational self-consistent field (CMCSCF)- based approach to investigate electron{atom/molecule scattering resonances. A modifi ed second quantization algebra adapted for biorthogonal spin orbitals has been applied to develop a quadratically convergent CMCSCF scheme. A new step-length control algorithm has been introduced in order to control the walk on the complex energy hypersurface and converge to correct CMCSCF stationary point. We have also developed a method (M1 method) based on the multiconfigurational spin tensor electron propagator (MCSTEP) to calculate resonance energies directly. These methods have been applied to investigate atomic and molecular scattering resonances. The test cases for our application were 2^P Be- and 2II_g N-_2 shape resonances. The position and the width of these resonances have been calculated for different complete active space choices. Convergence for CMCSCF calculations to a tolerance of 1:0 x 10^-10 a.u. for the energy gradient is achieved typically within ten iterations or less. The wide distribution of the values for the position and the width of the resonance reported in the literature has been explained by showing that there actually exists two distinct resonances which are close in energy. The resonance positions and widths from our calculation for the 2^IIg N-_2 shape resonance have been found to be very close to the experimental results. In another study, the effect of the orbitals with higher angular momentum has been investigated.

No description available.

Many Beyond Standard Model theories predict particles that couple strongly to top/anti-top quark pairs. This makes tt(bar) a promising signature for new physics searches. The analysis presented in this dissertation uses 20.3 fb⁻¹ of √s = 8 TeV pp collision data from the ATLAS experiment to search for evidence of new physics in the single-lepton plus jets tt(bar) decay channel. This is done by requiring one electron or muon, large missing transverse momentum and additional hadronic jets. The tt(bar) system is reconstructed using techniques optimized for either resolved or boosted event topologies. The results of the analysis are used to set upper limits on the production cross-section times branching ratio for heavy resonances decaying to tt(bar). These limits are interpreted in the context of several benchmark models including the leptophobic topcolor Z', the Randall-Sundrum Kaluza-Klein gluon (gKK), the Randall-Sundrum Kaluza-Klein graviton (GKK) and a spin-0 scalar particle.

As energias e larguras de escape das Ressonâncias Gigantes, são calculadas utilizando-se técnicas de projeção visando incluir as ressonâncias de partícula-única nos cálculos de RPA (\"Random Phase Approximation\"). As equações de RPA obtidas são complexas, e as larguras de escape são interpretadas como sendo a parte imaginaria das soluções em energia. Os cálculos são feitos para a RGE1( O16 ) e RGE0 ( Zr90 ). Para o Zr90, os espectros das partículas emitidas pela RGE0, prótons e nêutrons, são calculados através do modelo híbrido. Devido à existência de mais do que um tipo de partícula sendo emitida, as analises são feitas dentro da aproximação de independência entre os canais de partículas no formalismo do modelo híbrido. / The energy and the escape of the Giant Resonances are calculated utilizing the projection to include the single-particle resonances in complex RPA (Random Phase Approximation) calculations. The escape widths are interpreted as the imaginary parts of the energy solution of the RPA equations. The Calculations are performed for the RGE1 ( O16 ) and RGE0 ( Zr90 ). For the Zr90 the spectra of the particles ejected by the RGE0, protons and neutrons, are calculated within the hybrid model. The analysis are made through the channels independence in the hybrid model formalism.

As energias e larguras de escape das Ressonâncias Gigantes, são calculadas utilizando-se técnicas de projeção visando incluir as ressonâncias de partícula-única nos cálculos de RPA (\"Random Phase Approximation\"). As equações de RPA obtidas são complexas, e as larguras de escape são interpretadas como sendo a parte imaginaria das soluções em energia. Os cálculos são feitos para a RGE1( O16 ) e RGE0 ( Zr90 ). Para o Zr90, os espectros das partículas emitidas pela RGE0, prótons e nêutrons, são calculados através do modelo híbrido. Devido à existência de mais do que um tipo de partícula sendo emitida, as analises são feitas dentro da aproximação de independência entre os canais de partículas no formalismo do modelo híbrido. / The energy and the escape of the Giant Resonances are calculated utilizing the projection to include the single-particle resonances in complex RPA (Random Phase Approximation) calculations. The escape widths are interpreted as the imaginary parts of the energy solution of the RPA equations. The Calculations are performed for the RGE1 ( O16 ) and RGE0 ( Zr90 ). For the Zr90 the spectra of the particles ejected by the RGE0, protons and neutrons, are calculated within the hybrid model. The analysis are made through the channels independence in the hybrid model formalism.

京都大学 / 新制・課程博士 / 博士(理学) / 甲第24169号 / 理博第4860号 / 新制||理||1695(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)教授 田中 貴浩, 准教授 久徳 浩太郎, 教授 橋本 幸士 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

Flat-optics enable the miniaturization of many traditional bulk photonic devices routinely used in optical modulation and detection in telecommunication systems, biosensing and microscopic imaging in biomedical research, and light detection and ranging (LiDAR) used in automobile, military and surveillance applications. The backbone of typical flat-optic devices are the metasurfaces comprising structured nanoparticle lattices embedded in flat layer of traditional dielectric or semiconductor optical materials. The metasurface lattices can create optical resonances by exploiting different aspects of the light-matter interaction, e.g., light absorption, radiation, scattering and diffraction by the nanoparticles array. Such resonances are essential for the efficient optical interactions performed by the flat-optic devices, for example, enhancing nonlinear second-harmonic generation for optical frequency modulators, or enhancing light absorption in photodetectors. This Ph.D. dissertation reports the mechanisms of exciting and tailoring the metasurface lattice-controlled resonances using metal nanoparticle arrays. Exhibiting localized surface plasmon effects, metal particles can dramatically enhance the light field intensity under resonance conditions. Nevertheless, by nature, metal particles concurrently exhibit high absorption, radiation, and scattering losses, which cannot be sufficiently suppressed by the localized surface plasmon resonances. Almost two decades ago, researchers theoretically estimated that the benefits of the plasmonic field enhancement could still be harnessed by suppressing the scattering loss by organizing such lossy metal particles in a periodic lattice formation. In contrast to the low-Q localized resonances, such an engineered lattice arrangement could excite high-Q nonlocalized resonances, which are now often called as lattice plasmon or surface lattice resonances. Notwithstanding, the efforts on the experimental validation of such a concept were not succeeding as per expectation in terms of the resonance Q-factors. Thus, prior to the work accomplished in this dissertation, it was largely believed by the photonics community that, it is the 'lossy' plasmonic metal particles that do not allow to excite the high-Q resonances as per the minimum requirements in the practical flat optic applications. As a primary contribution to my Ph.D. dissertation, we successfully debunk that myth. In our work, we systematically proved that the non-localized lattice resonances can still be excited in 'lossy' metal nanoparticle arrays. Precisely, we improved both the design of the metasurface lattices and their fabrication and characterization techniques to eventually observe the high-Q lattice resonances as per the theoretical prediction. Our primary success later inspired us to analyze the systems more profoundly to make them suitable for different types of practical applications, which ultimately resulted in additional secondary successful projects described in my Ph.D. dissertation. The success of these projects would allow us in the future to utilize the nonlocalized plasmonic metasurface lattice-controlled resonances in a diverse range of flat integrated photonics applications, such as free-space light modulation and detection, which may rely on the nonlinear or electro-optical light-matter interaction in the flat thin-film region. We believe that the outcome of this dissertation will pave the way to designing and manufacturing efficient flat meta-optic devices for real-life applications, particularly in the telecommunication and medical sectors for the utmost betterment of human civilization.

<p> The limitations of the conventional control system due to the corona discharge are discussed. An improved system employing a parallel feedback loop to modulate the terminal stripper is described. Finally an experiment is described whereby the performance of this system is measured and compared with the original system performance.</p> / Thesis / Master of Science (MSc)

No description available.

Cavity flow-acoustic resonances may occur when a fluid stream flows past a recessed cavity in a wall. These resonances may lead to high unsteady pressure levels. The resonance involves a coupling between the instability wave which propagates downstream on the shear-layer that spans the open face of the cavity, and acoustic waves that propagate back upstream inside and outside the cavity. These waves are coupled by the scattering processes at the ends of the cavity. Previous theoretical research considered cavities in a wall that bounds an infinite stream. In many of the experiments on cavity resonances, however, the cavity is placed in a side wall of a wind tunnel. When the surrounding wind tunnel walls are not acoustically treated, the resonances can be very strong. My research is a theoretical investigation of the case of a cavity in a side wall of a wind tunnel. Recently, a mode trapping phenomenon has been proposed as an explanation for the very strong cavity resonances in the wind tunnel case. The mode trapping occurs when the critical frequency of a mode in the tunnel-cavity region is slightly lower than the critical frequency of the corresponding mode in the tunnel region. The region between these two critical frequencies is defined as a frequency window. Experiments show that very high pressure levels are observed in these frequency windows. The goal of my research is to develop a global theory of cavity resonances in the wind tunnel geometry. The global theory couples solutions for the instability wave and the acoustic waves through scattering analyses at the ends of the cavity. Resonance frequencies, spatial mode shapes and linear growth rates are predicted. The theoretical predictions are consistent with experimental measurements and demonstrate that the mode trapping phenomenon explains the experimentally observed behavior.