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Full-Text Articles in Physical Sciences and Mathematics

Quantum Chaos, Integrability, And Hydrodynamics In Nonequilibrium Quantum Matter, Javier Lopez Piqueres Mar 2024

Quantum Chaos, Integrability, And Hydrodynamics In Nonequilibrium Quantum Matter, Javier Lopez Piqueres

Doctoral Dissertations

It is well-known that the Hilbert space of a quantum many-body system grows exponentially with the number of particles in the system. Drive the system out of equilibrium so that the degrees of freedom are now dynamic and the result is an extremely complicated problem. With that comes a vast landscape of new physics, which we are just recently starting to explore. In this proposal, we study the dynam- ics of two paradigmatic classes of quantum many-body systems: quantum chaotic and integrable systems. We leverage certain tools commonly employed in equilibrium many-body physics, as well as others tailored to the …


A New Galactic Wind Model For Cosmological Simulations, Shuiyao Huang Feb 2022

A New Galactic Wind Model For Cosmological Simulations, Shuiyao Huang

Doctoral Dissertations

The propagation and evolution of cold galactic winds in galactic haloes is crucial to galaxy formation models. However, modelling of this process in hydrodynamic simulations of galaxy formation is over-simplified owing to a lack of numerical resolution and often neglects critical physical processes such as hydrodynamic instabilities and thermal conduction. In this thesis, I propose an analytic model, Physically Evolved Winds (PhEW), that calculates the evolution of individual clouds moving supersonically through a uniform ambient medium. The model reproduces predictions from very high resolution cloud-crushing simulations that include isotropic thermal conduction over a wide range of physical conditions. I also …


Ly Alpha Emission From Cosmic Structure. I. Fluorescence, Ja Kollmeier, Z Zheng, R Dave, A Gould, N Katz, J Miralda-Escude, Dh Weinberg Jan 2010

Ly Alpha Emission From Cosmic Structure. I. Fluorescence, Ja Kollmeier, Z Zheng, R Dave, A Gould, N Katz, J Miralda-Escude, Dh Weinberg

Astronomy Department Faculty Publication Series

We present predictions for the fluorescent Lyα emission signature arising from photoionized, optically thick structures in smoothed particle hydrodynamic cosmological simulations of a ΛCDM universe using a Monte Carlo Lyα radiative transfer code. We calculate the expected Lyα image and two-dimensional spectra for gas exposed to a uniform ultraviolet ionizing background as well as gas exposed additionally to the photoionizing radiation from a local quasar, after correcting for the self-shielding of hydrogen. As a test of our numerical methods and for application to current observations, we examine simplified analytic structures that are uniformly or anisotropically illuminated. We compare these results …


Galactic Bulge Feedback And Its Impact On Galaxy Evolution, Shikui Tang Sep 2009

Galactic Bulge Feedback And Its Impact On Galaxy Evolution, Shikui Tang

Open Access Dissertations

Galactic bulges of early-type spirals and elliptical galaxies comprise primarily old stars, which account for more than half of the total stellar mass in the local Universe. These stars collectively generate a long-lasting feedback via stellar mass loss and Type Ia supernovae. According to the empirical stellar mass loss and supernova rates, the stellar ejecta can be heated to more than 107 K, forming a very hot, diffuse, and ironrich interstellar medium. Conventionally a strong galactic wind is expected, especially in low- and intermediate-mass early-type galaxies which have a relatively shallow potential well. X-ray observations, however, have revealed that both …


Star Formation And Feedback In Smoothed Particle Hydrodynamic Simulations - I. Isolated Galaxies, G Stinson, A Seth, N Katz, J Wadsley, F Governato, T Quinn Jan 2006

Star Formation And Feedback In Smoothed Particle Hydrodynamic Simulations - I. Isolated Galaxies, G Stinson, A Seth, N Katz, J Wadsley, F Governato, T Quinn

Astronomy Department Faculty Publication Series

We present an analysis of star formation and feedback recipes appropriate for galactic smoothed particle hydrodynamics simulations. Using an isolated Milky Way-like galaxy, we constrain these recipes based on well-established observational results. Our star formation recipe is based on that of Katz with the additional inclusion of physically motivated supernova feedback recipes. We propose a new feedback recipe in which Type II supernovae are modelled using an analytical treatment of blastwaves. With this feedback mechanism and a tuning of other star formation parameters, the star formation in our isolated Milky Way-like galaxy follows the slope and normalization of the observed …


Cosmological Simulations With Scale-Free Initial Conditions. I. Adiabatic Hydrodynamics, Jm Owen, Dh Weinberg, Ae Evrard, L Hernquist, N Katz Jan 1998

Cosmological Simulations With Scale-Free Initial Conditions. I. Adiabatic Hydrodynamics, Jm Owen, Dh Weinberg, Ae Evrard, L Hernquist, N Katz

Astronomy Department Faculty Publication Series

We analyze hierarchical structure formation based on scale-free initial conditions in an Einstein-de Sitter universe, including a baryonic component with Ωbary = 0.05. We present three independent, smoothed particle hydrodynamics (SPH) simulations, performed at two resolutions (323 and 643 dark matter and baryonic particles) and with two different SPH codes (TreeSPH and P3MSPH). Each simulation is based on identical initial conditions, which consist of Gaussian-distributed initial density fluctuations that have a power spectrum P(k) k-1. The baryonic material is modeled as an ideal gas subject only to shock heating and adiabatic heating …