Occupy This: The Effect of Income Inequality on GDP Per Capita Growth Using Panel Data in the United States from 1963 to 2009

Income inequality and its relationship to long-term GDP per capita growth has been researched for decades since the development of the Kuznet’s Curve. Theoretical and empirical research has shown mixed results including positive, negative, non-existent, or statistically insignificant relationships. Empirical research on income inequality and economic growth in the United States has also shown mixed results. In addition to using existing data, this paper uses originally-constructed Gini Coefficients from 2005 to 2009. A statistically significant negative correlation between income inequality, and both short-term growth and long-term growth is found in the analysis of this data. Finally, this paper attempts to justify a causal relationship between income inequality and long-term growth

Mechanistic Contributions To Geomorphic Changes Of State

Transitions abound in geomorphology. Be it the transition from static to dynamic or the shift in a dune field from one dune morphology to another, many questions involve changes of state. This dissertation empirically studies state changes over three scales with an emphasis placed on contributing mechanical factors. First, we examine the transition from static to dynamic at the grain scale in bedload transport (hopping, rolling, and skipping of grains along a riverbed). Transport of grains is continuous at high rates but becomes unpredictable near the threshold of motion. Results show that this unpredictability is similar to how avalanches occur in a sandpile. Transport events are similar in size and merge as transport increases. Grain displacement in the system appears governed by mobile grain-bed kinetic energy exchange. Next, we study the static to dynamic transition at the scale of many grains by examining how soil mechanical properties influence the threshold of motion. Sandbed experiments indicate that, when moisture is the primary variable, shear strength is proportional to the threshold of motion. Finally, we examine a landscape scale pattern transition that arises from the physics of sediment transport interacting with vegetation in a dune field. The onset of vegetation destroys a fluid instability that is fundamental for maintaining the dune pattern prevalent in the dune fields center. Plants destroy the mechanism maintaining the dune field pattern which helps give rise to a qualitative shift in dune morphology. This work highlights the continued relevance of physically informed experiments and field studies for understanding geomorphic transitions from the grain to the landscape scale

On the Optimal Choice of Spin-Squeezed States for Detecting and Characterizing a Quantum Process

Quantum metrology uses quantum states with no classical counterpart to measure a physical quantity with extraordinary sensitivity or precision. Most metrology schemes measure a single parameter of a dynamical process by probing it with a specially designed quantum state. The success of such a scheme usually relies on the process belonging to a particular one-parameter family. If this assumption is violated, or if the goal is to measure more than one parameter, a different quantum state may perform better. In the most extreme case, we know nothing about the process and wish to learn everything. This requires quantum process tomography, which demands an informationally-complete set of probe states. It is very convenient if this set is group-covariant -- i.e., each element is generated by applying an element of the quantum system's natural symmetry group to a single fixed fiducial state. In this paper, we consider metrology with 2-photon ("biphoton") states, and report experimental studies of different states' sensitivity to small, unknown collective SU(2) rotations ("SU(2) jitter"). Maximally entangled N00N states are the most sensitive detectors of such a rotation, yet they are also among the worst at fully characterizing an a-priori unknown process. We identify (and confirm experimentally) the best SU(2)-covariant set for process tomography; these states are all less entangled than the N00N state, and are characterized by the fact that they form a 2-design.Comment: 10 pages, 5 figure