Physics
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Item Reorganizing Nothingness(2017) Misner, Charles WThis note is directed to scientists who intend to help wide audiences better understand current science progress. It sketches, in mostly qualitative descriptions, what is known about simple black holes. It describes black holes when they are no longer importantly interacting with other astronomical objects. Thus, it does not explore black holes seen to be currently acquiring mass by absorbing ordinary matter in accretion disks. Nor do I try to explain how matter just outside the black hole horizon can be expelled in violent jets powered by the energy stored in the gravitational fields of rotating black holes. Brief descriptions of simple black holes explain that BHs can be formed from ordinary matter in large stars that find no non-gravitational forces sufficient to overcome the intense gravity of extremely large masses at extreme densities. Where this note differs is when the simple descriptions suggest that, after forming and entering beyond the BH horizon, the collapsing matter is crushed beyond the scope of current physics nearly into a point, inside the BH, that we can’t observe. I insist that, instead, the matter is crushed and then disposed of by being flushed out of our universe in a tube of huge and increasing spatial length. A mathematical appendix explores this idea in a little detail. I suggest that many low curvature spacetime regions inside the BH are very robust consequences of Einstein’s equations and require a new vocabulary in their description. There I choose analog words to present my viewpoint. I find a use for phrases such as: nothingness; enzymatic matter; phase transitions; recuse; autonomic spacetime creation.Item Simulations of Accretion Mechanisms and Observational Signatures of Black Hole Accretion Disks(2019) Smith, Megan; McKinney, Jonathan C; Physics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Black holes have been a subject of fascination since they were first theorized about over a century ago. There are many questions about them left unanswered. One of these questions is how matter is accreted onto these objects when the plasma around them is rotating in an accretion disk. An answer to this question is likely to be found in the magnetohydrodynamic processes that occur in the plasma, which require highly sophisticated numerical simulations to explore. In this thesis, I describe an analysis of one magnetohydrodynamic instability found in these simulations as well as the observational signatures it produces, which might be recognized in observations of these systems. For the remainder of this thesis, I will discuss the formation and evolution of a formal near-peer mentoring program for women in the University of Maryland physics department. Mentoring programs have been shown to have a number of benefits for both mentors and mentees. Primary among them is an increased sense of belonging and science identity, which is linked to increased retention. Given the so-called "leaky pipeline" problem of women leaving physics, a field where they are already underrepresented, efforts to improve retention are vital and peer mentoring is one way to do this.Item Non-Perturbative Methods in Quantum Field Theory and Quantum Gravity(2016) de la Fuente, Anton; Sundrum, Raman; Physics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This thesis considers non-perturbative methods in quantum field theory with applications to gravity and cosmology. In particular, there are chapters on black hole holography, inflationary model building, and the conformal bootstrap.