Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 52 for “"Correlators"”.
-
Predictions and Constraints of Cosmological Correlators
<p>In this dissertation, we study the role of correlation functions in Cosmology. The study is bidirectional: We explore the constraints that correlation functions gathered from data impose on different theories; we also analyze the constraints that get imposed on correlation functions given …
-
Bandpass filters for unconstrained target recognition and their implementation in coherent optical correlators
An up-dateable correlator is simulated which is based on the non-degenerate four wave mixing (NDFWM) interaction in the photorefractive material bismuth silicon oxide (Bi12SiO20). Specifically, it is shown that variable bandpass filters can be implemented directly in the correlator by adjusting the …
-
Ultra-wideband Spread Spectrum Communications using Software Defined Radio and Surface Acoustic Wave Correlators
… performance in noisy environments. Use of SAW correlators reduces the complexity and power requirements of the receiver architecture by eliminating many of the components needed and reducing the signal processing and timing requirements necessary for digital matched filtering of the complex …
-
The Polyakov loop and its correlators in higher representations of SU(3) at finite temperature
We have calculated the Polyakov loop in representations D=3,6,8,10,15a,15s,24,27 and diquark and baryonic Polyakov loop correlation functions with fundamental sources in SU(3) pure gauge theory and 2-flavour QCD with staggered quarks and Qbar Q-singlet correlation functions with sources in the …
-
Design and analysis of high-speed optical correlators for multiwavelength optical header recognition and optical code division multiple access
Optical correlators arc attractive elements for packet-switched optical networks because they enable the headers of high-speed optical packets to be processed and recognised "on-the-fly", thus, switching the packets to different destinations without the need for optical-to-electrical and …
-
Rapidity evolution of observables at high energies using the Gaussian truncation
… rotations, called Wilson Lines, as well as their correlators. The rapidity evolution of these correlators is given by the JIMWLK equation. However, this leads to an infinite hierarchy of coupled differential equations, which are impossible to solve in a closed form and truncations become …
-
Dark signalling and code division multiple access in an optical fibre LAN with a bus topology
… of optical CDMA schemes using incoherent correlators is the effect of optical beating due to the presence of multiple incoherent optical signals at the receiver photodiode. The network proposed and analysed in this thesis avoids beating between multiple optical fields because it only uses …
-
Investigating the 4-point truncation of the JIMWLK evolution equation
… describes the rapidity evolution of Wilson line correlators in the CGC framework, which are crucial for computing cross-sections in DIS. However, JIMWLK generates an infinite hierarchy of coupled integro-differential equations (the Balitsky hierarchy), for which no analytical or numerical …
-
A gauge-invariant, symmetry-preserving truncation of JIMWLK
… described in terms of Wilson-lines and their correlators. The energy-dependence of these correlators is given by the JIMWLK (Jalilian-Marian+Iancu+McLerran+Weigert+Leonidov+Kovner) equa- tion which, when applied to a correlator, generates an infinite tower of coupled Dyson-Schwinger- like …
-
Exclusive J/Ψ Vector-Meson production in high-energy nuclear collisions: a cross-section determinaton in the Colour Glass Condensate effective field theory and a feasibility study using the STARlight Monte Carlo event generator
… field theory. Rapidity-averaged n-point correlators are used to describe the strong interaction part of this process. The JIMWLK equation can be used to predict the energy evolution of a correlator. In order to facilitate practical calculations, an approximation scheme must be employed. …
-
Causality and unitarity in the early universe
… how fundamental principles shape cosmological correlators. This thesis examines some of the outcomes of this effort. The first three chapters are an introduction to theoretical cosmology with standard material on scattering amplitudes and the wavefunction of the universe. The following two …
-
The Vulcanization Transition and the Amorphous Solid State It Yields: A Statistical Mechanical Perspective
… states. In addition, we study certain density correlators associated with the vulcanization transition, which are accessible via various experimental techniques. These correlators turns out to contain essential information about both the vulcanization transition and the emergent amorphous solid …
-
Control and detection of complex fields in spatio-temporal optical systems
… in optical fields. Interferometric cross correlators detect temporal information by using spatial processes that can achieve higher resolution than direct temporal processes can achieve. An analysis of interferometric cross correlators is presented, and the signal-to-noise ratio that can …
-
The cosmological bootstrap and the analytic wavefunction
… symmetry, and analyticity on cosmological correlators. In this thesis we explore the consequences of two such principles: unitarity and analyticity. We show that unitarity implies a set of consistency relations among wavefunction coefficients in perturbation theory, and these relations can …
-
Early Seeds and Cosmic Skies: Quantum Origins of the Universe and Insights from Large-Scale Structure
… a technique to better understand cosmological correlators, the primary observable in the inflationary universe. Traditionally, cosmological correlators are computed with the standard but complicated Schwinger-Keldysh in-in formalism. Here, we show that for non-dissipative systems, we can …
-
The Phase of the Cosmological Wavefunction
… how such principles constrain cosmological correlators and the wavefunction of the universe (also referred to as the cosmological wavefunction) in inflationary spacetimes. Using the Effective Field Theory of Inflation (EFToI), the first part of the thesis classifies all parity-even graviton …
-
Études in Ambitwistor Strings - Exploring new models, higher loops and curved backgrounds
… the splitting of 4-vector-valued fermion correlators on the sphere into a product of two terms, each involving left/right-handed spinors only. We use this splitting result to derive a formula for $ \mathcal{N} = 4 $ super Einstein-Yang-Mills in twistor space based on the refined 4d …
-
Charmonium correlation and spectral functions in quenched lattice QCD at finite temperature
… to control cut-off effects in the charmonium correlators and spectral functions. In particular, our finest lattices have a very small lattice spacing, i.e. $a=0.01$ fm. Using the Maximum Entropy Method we have reconstructed the spectral functions at both temperature below and above the …
-
Accelerating software radio astronomy FX correlation with GPU and FPGA co-processors
… radio brightness distribution. Radio astronomy correlators have huge computation demands and this dissertation focuses on the computational aspects of correlation, concentrating on the X-engine stage of the correlator.
-
Euclidean Dynamical Triangulations: Running Couplings and Curvature Correlation Functions
… removing the disconnected contributions to the correlators, we find universal behavior in these correlators, including a power-law drop-off with distance with a power consistent with -10. We also explore a means to extract the coefficient of the $R^2$ term in the low energy effective action. We …
Page 1 of 3