Physical Sciences and Mathematics Commons^™

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 …

Composite Network Of Actin And Microtubule Filaments, Self-Organization And Steady-State Dynamics, Leila Farhadi

Doctoral Dissertations

Actin and microtubule filaments, with their auxiliary proteins, enable the cytoskeleton to perform vital processes in the cell by tuning the organizational, mechanical properties and dynamics of the network. Despite their critical importance and interactions in cells, we are only beginning to uncover information about the composite network. Here, I use florescence microscopy to explore the role of filaments characteristics, interactions and activities in the self-organization and steady-state dynamics of the composite network of filaments. First, I discuss active self-organization of semiflexible actin and rigid microtubule filaments in the 2D composite network while myosin II and kinesin-1 motor proteins propel …

Dynamic Neuromechanical Sets For Locomotion, Aravind Sundararajan

Doctoral Dissertations

Most biological systems employ multiple redundant actuators, which is a complicated problem of controls and analysis. Unless assumptions about how the brain and body work together, and assumptions about how the body prioritizes tasks are applied, it is not possible to find the actuator controls. The purpose of this research is to develop computational tools for the analysis of arbitrary musculoskeletal models that employ redundant actuators. Instead of relying primarily on optimization frameworks and numerical methods or task prioritization schemes used typically in biomechanics to find a singular solution for actuator controls, tools for feasible sets analysis are instead developed …

Extreme Dynamics Of Nanomaterials Under High-Rate Mechanical Stimuli, Wanting Xie

Doctoral Dissertations

Nanomaterials demonstrate novel mechanical properties attributed to the extremely large interfacial area. At quasi-static rates, the interfacial interactions are crucial in mechanical behaviors, however, materials under extreme mechanical stimuli are rarely studied at nanoscale. With an advanced laser-induced projectile impact test, we perform supersonic impact of micro-projectiles on polymer films, multilayer graphene, carbon- based nanocomposites membranes as well as individual micro-fibers, to study the interface interactions in the high-rate regime, and develop a simplified model to characterize the ballistic performance of materials.

Emergent Phenomena In Quantum Critical Systems, Kun Chen

Doctoral Dissertations

A quantum critical point (QCP) is a point in the phase diagram of quantum matter where a continuous phase transition takes place at zero temperature. Low-dimensional quantum critical systems are strongly correlated, therefore hosting nontrivial emergent phenomena. In this thesis, we first address two decades-old problems on quantum critical dynamics. We then reveal two novel emergent phenomena of quantum critical impurity problems. In the first part of the thesis, we address the linear response dynamics of the $(2+1)$-dimensional $O(2)$ quantum critical universality class, which can be realized in the ultracold bosonic system near the superfluid (SF) to Mott insulator (MI) …

Structural Dynamics And Charge Transport In Room Temperature Ionic Liquids, Philip James Griffin

Doctoral Dissertations

Room temperature ionic liquids are an important class of materials due to their chemical tunability and numerous advantageous physicochemical properties. As a result, ionic liquids are currently being investigated for use in a wide array of chemical and electrochemical applications. Despite their great potential, however, the relationship between the chemical structure and physicochemical properties of ionic liquids is not well understood.

To this end, this dissertation presents experimental studies of the reorientational structural dynamics and charge transport properties of a variety of room temperature ionic liquids using quasielastic light scattering spectroscopy and broadband dielectric spectroscopy.

Studies of a series of …