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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
241

Exceptional points and adiabatic evolution in optical coupled mode systems

Yang, Guang 30 August 2023 (has links)
Quantum and classical frameworks form two perspectives for describing physical systems. Their formulation also presents interesting isomorphism: for example, the Schrodinger equation can find its classical correspondence in the paraxial Helmholtz equation, and coherent atomic population transfers is analogous to coupling dynamics in waveguides. In classical coupled mode systems, quantum notion can be manifested in the following ways: (1) adiabatic (i.e., sufficiently slow) evolution of the Hamiltonian enables robust mode conversion and light transfer, where the dynamics is carried out in predominantly one eigenmode; (2) non-Hermitian Hamiltonians give rise to peculiar singularities known as exceptional points (EPs), associated with not only degenerate eigenvalues but coalescent eigenvectors. In this dissertation, we explore the above principles in light manipulation, sensing, and photonic emulation. First, we numerically demonstrate two examples of photonic devices based on adiabatic evolution engineering. We present a coupled waveguide system analogous to the atomic physics process of stimulated Raman adiabatic passage, where the principle of adiabaticity not only allows high-extinction polarization mode splitting, but also counterintuitively mitigates the losses from the plasmonic structure involved. We show a modal hybridization effect in rib waveguide geometry that allows the mode to adiabatically evolve from one polarization to its orthogonal state upon electro-optic modulation in thin film lithium niobate, enabling an actively switchable polarization converter. We propose a generic EP emulator based on programmable photonics to tackle the challenging implementation of EP. Our approach combines on-chip operations of coupling, loss and detuning based on generic photonic modules (Mach-Zehnder interferometers), and a discrete scheme for mapping Hamiltonians to common mesh architecture. We demonstrate multiple exemplary EP functionalities, including loss-induced transparency, encircling second-order EPs in the PT and anti-PT symmetry picture, and a third-order EP. The proposed EP emulator marks a new paradigm for discrete, \textit{in situ} programming of EPs and multi-functional, repurposable EP devices. We also present our preliminary work on NV center-induced EPs. In contrast to conventional fluorescence-based schemes for addressing NV centers, we leverage NV centers' absorption to bring a coupled ring resonator system to an EP and numerically demonstrate the emerging dynamics. Our primary numerical results promise proof-of-concept magnetometry, combining NV centers' response to magnetic and microwave fields with the sensitivity enhancing nature of EP. This dissertation sheds light on unconventional photonics inspired by quantum-like principles. / 2025-08-29T00:00:00Z
242

An Area-Efficient Architecture for the Implementation of LDPC Decoder

Yang, Lan 25 April 2011 (has links)
No description available.
243

Further Development of A Data Analysis Framework for The MOLLER Experiment atJefferson Lab

Anik, Md Mahmudul Hasan 11 June 2018 (has links)
No description available.
244

Integrity Monitoring Techniques for Vision Navigation Systems

Baine, Nicholas Allen 04 September 2012 (has links)
No description available.
245

Exchange rate dynamics in a continuous-time model of uncovered interest parity with central bank intervention

Moh, Young-Kyu 05 September 2003 (has links)
No description available.
246

Three essays on the term structure of interest rates

Lim, Hyoung-Seok 18 June 2004 (has links)
No description available.
247

Exotic superconductivity associated with parity symmetry breaking / パリティ対称性の破れに関連するエキゾチック超伝導

Kanasugi, Shota 23 March 2022 (has links)
京都大学 / 新制・課程博士 / 博士(理学) / 甲第23688号 / 理博第4778号 / 新制||理||1684(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 柳瀬 陽一, 教授 川上 則雄, 教授 松田 祐司 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM
248

Lnc-EPCAM AND Lnc-BHLHE41 AS RNA REGULATORS OF BREAST CANCER AND BREAST CANCER PREVENTION

Barton, Maria January 2017 (has links)
The objective of this study was to unveil a novel area of gene regulation in breast cancer and breast cancer prevention through the study of a recent discovered class of genetic regulators named long non-coding RNAs (lncRNAs). LncRNAs are RNA molecules longer than 200 nucleotides that are not translated into proteins, but regulate the transcription of genes involved in different cellular processes, including differentiation, cancer initiation and progression. The link between lncRNAs and cancer is well documented in the literature. More recently, their relevance in the transcription field is beginning to be explored and their roles have been found to vary from guiding proteins to the genome to scaffolding proteins complexes needed for the transcription of a specific gene. Initial transcriptome analysis of normal breast of parous and nulliparous postmenopausal women revealed that several lncRNAs are differentially expressed in the parous breast. This observation provided evidence of a potential role of lncRNAs in the regulation of transcription and their function in pregnancy’s preventive effect in reducing the lifetime risk of developing breast cancer. Specifically, RNA sequencing of healthy postmenopausal breast tissue biopsies from eight parous and eight nulliparous women using Illumina platform was performed. The sequencing results showed that there are 42 lncRNAs differentially expressed between parous and nulliparous breast tissue. These data led to the hypothesis that these novel lncRNAs may be drivers in the process of development that occurs in the mammary gland during pregnancy, providing protection against breast cancer. After analysis of these 42 lncRNAs using bioinformatics tools, review of the scientific literature, and real-time PCR analysis, two lncRNAs (lncBHLHE41 and lncEPCAM) were selected to be tested in vitro, using different molecular techniques in human epithelial breast cell lines to determine their relevance in breast cancer. This project provided novel information on lncRNAs induced by pregnancy in the breast tissue, and identified two lncRNAs as potential key regulators in breast differentiation and cancer progression. The manipulation of these lncRNAs led to evidence of their function in vitro and, using xenograft studies, we determined their relevance in vivo. Although treatment for cancer using lncRNAs as targets is in its infancy at the clinic, the advancement in knowledge and technology to study their relevance in disease could lead to the development of therapeutics for breast cancer and breast cancer prevention in the near future. / Biochemistry
249

Terms of trade effects on PPP and incomes of primary-commodity exporting countries

Koya, Sharmistha N. 02 October 2007 (has links)
This dissertation investigates the commodity currency argument of primary and secondary effects of the terms of trade on exchange rates and real income, respectively. The Johansen procedure of cointegration testing is applied to dynamic models for a set of four developed countries (New Zealand, Australia, Norway and Iceland) and five less developed countries (Colombia, India, Malaysia, Thailand and Venezuela) each against it's major trading partner and the United States. The stationarity of the real exchange rates as well as cointegration between the nominal exchange rates and the ratio of national price-levels (price-ratio) are analyzed for two sets of data (annual and a relatively shorter quarterly) and for two different price measures (GDP deflator and CPI). The hypothesis of the terms of trade effects is investigated by including the terms of trade variable in the models of real exchange rates and models of nominal exchange rates and price-ratios. For developed countries, using annual data, real exchange rates are found to be stationary without the terms of trade in eleven cases, and on including the terms of trade evidence of cointegration is found in three further cases. For the quarterly data of the developed countries, there is some evidence of the real exchange rate being stationary without the terms of trade and some evidence of cointegration between the real exchange rates and the terms of trade for both price indices. Analysis of the long-run equilibrium relationship between the nominal exchange rate and price-ratio without the terms of trade showed some evidence of a cointegrating relationship. On including the terms of trade strong evidence of cointegration is obtained for New Zealand and Austra1ia but not for Norway. Moreover, while evidence for the long-run equilibrium relationships of purchasing power parity are mixed there is strong evidence of improvement in the terms of trade leading to appreciating exchange rates. Also, the terms of trade are found to be exogenous between small countries (New Zealand-Australia). Only quarterly data and CPI are used for the less dev.~loped countries. Results on stationarity of the real exchange rate, the equilibrium relationship between the exchange rates and price-ratio, and the role of terms of trade are again mixed. Finally, the short-run effects of the terms of trade on real income are investigated for New Zealand, Australia and Norway using quarterly data. Dynamic models of first, the real income and terms of trade and real income, terms of trade, and, second, the real exchange rates are analyzed. Validity of the commodity currency argument is evidenced only in some of the three-variable models. / Ph. D.
250

Precision Measurement of the Proton's Weak Charge using Parity-Violating Electron Scattering

Duvall, Wade Sayer 15 November 2017 (has links)
The Qweak experiment has precisely determined the weak charge of the proton Qp w by measuring the parity-violating asymmetry in elastic electron-proton scattering at a low momentum transfer of Q2 = 0.0249 (GeV/c)2 . Qpw has a definite prediction in the Standard Model, and a value of sin2 θW can be extracted from it for comparison with other neutral current observables. Qweak measured the weak charge of the proton to be Qpw(P V ES) = 0.0719 ± 0.0045, which is consistent with the Standard Model value of Qp w(SM) = 0.0708 ± 0.0003. Qweak ran at the Thomas Jefferson National Accelerator Facility for two and a half years and was installed in experimental Hall C. A 180µA beam of longitudinally polarized electrons at 1.16 GeV scattered off a liquid hydrogen target of unpolarized protons. The electrons were collimated to an acceptance of 5.8◦ to 11.6◦ and then passed through a magnetic spectrometer and onto quartz Čerenkov detector bars. A detailed description of the theory and motivation behind the Qweak experiment is given. An overview of the Qweak apparatus and an in-depth discussion of the luminosity monitor performance is presented. A general overview of the Qweak analysis is also presented, with a focus on the beamline background correction, the nonlinearity measurement, and the simulation to constrain error for a rescattering effect. Also detailed here is the final, unblinded Qweak result, which determined Qpw to 6.2% and provided the highest precision measurement of sin2θW at low energy. / PHD

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