京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第22028号 / 理博第4532号 / 新制||理||1651(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 向山 信治, 准教授 Antonio De Felice, 教授 鶴 剛 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

This thesis is devoted to developing a group-theoretical approach towards quantum gravity in (Anti)-de Sitter spacetime. We start with a comprehensive review of the representation theory of de Sitter (dS) isometry group, focusing on the construction of unitary irreducible representations and the computation of characters. The three chapters that follow present the results of novel research conducted as a graduate student. Chapter 4 is based on [1]. We provide a general algebraic construction of higher spin quasinormal modes of de Sitter horizon and identify the boundary operator insertions that source the quasinormal modes from a local QFT point of view. Quasinormal modes of a single higher spin field in dSD furnish two nonunitary lowest-weight representations of the dS isometry group SO(1,D). We also show that quasinormal mode spectrums of higher spin fields are precisely encoded in the Harish-Chandra characters of the corresponding SO(1,D) unitary irreducible representations. Chapter 5 is based on work with D. Anninos, F. Denef and A. Law [2]. With potential application to constraining UV-complete microscopic models of de Sitter quantum gravity, we compute de Sitter entropy as the logarithm of the sphere path integral, for any possible low energy effective field theory containing a massless graviton, in arbitrary dimensions. The path integral is performed exactly at the one-loop level. The one-loop correction to the dS entropy is found to take a universal “bulk−edge” form, with the bulk part being an integral transformation of a Harish-Chandra character encoding quasinormal modes spectrum in a static patch of dS and the edge part being the same integral transformation of an edge character encoding degrees of freedom frozen on the dS horizon. In 3D de Sitter spacetime, the one-loop exact entropy is promoted to an all-loop exact result for truncated higher spin gravity, the latter admitting an SL(n,C) Chern-Simons formulation with n being the spin cut-off. Chapter 6 is based on [3]. Inspired by [2], we revisit the one-loop partition function of any higher spin field in (d + 1)-dimensional Anti-de Sitter spacetime and show that it can be universally expressed as an integral transform of an SO(2, d) bulk character and an SO(2, d − 2) edge character. We apply this character integral formula to various higherspin Vasiliev gravities and find miraculous (almost) cancellations between bulk and edge characters, leading to striking agreement with the predictions of higher spin holography. We also comment on the relation between our character integral formula and Rindler-AdS [4] thermal partition functions.

<p> The separation of distilled water and coconut fatty acid (CNFA) was investigated in a 4 in. x 16 in. vertical gravity decanter to determine the most significant design variables. The design variables studied were tangential versus perpendicular feed flow, height/diameter ratio, the total feed flow rate, the temperature and the intertace position with respect to feed inlet. The criteria used were the calculated immiscible concentration of water in CNFA overflow (Cw) and that of CNFA in water underflow (Co), The test conditions were arranged according to a Central Composite Design based on Box Method of Experimentation. Two levels of inlet geometry and five levels of each of the other four variables were studied. The range of variables were 1. Inlet geometry Tangential and Perpendicular Feed Flow 2. Height/Diameter Ratio 3/1 to 4/1 3· Total Feed Flow rate 160 cc/min. to 320 cc/min. 4. Temperature 40° to 80°c. 5· Interrace Position 2" below feed inlet to 2" above feed inlet The Overall residence time in the decanter ranged from 7.5 to 12.5 minutes. The drop size distribution of the incoming dispersion was measured by taking photomicrographs for all the runs. </p> <p> It was found that the tangential feed flow was slightly better but not significantly better for the separation of two immiscible liquids. Statistical analysis revealed that 95% confidence level height/diameter ratio, flow rate and temperature, respectively, are the most important design variables for the separation of CNFA from water underflow. The dependence of Cw on height/diameter ratio of Co on the interface position was interpreted to mean that the theoretical, plug flow residence time within each phase is the most important design variable. Interaction between variables and second order constants were not found significant at 95% confidence level. Sedimentation rather than coalescence appeared to be the controlling factor in the present study. </p> / Thesis / Master of Engineering (MEngr)

No description available.

published_or_final_version / Physics / Doctoral / Doctor of Philosophy

No description available.

No description available.

No description available.

No description available.

No description available.