Statistical, Nonlinear, and Soft Matter Physics Commons^™

Synthesizing Viscoelasticity: Living Polymers, Micro-Macro Relations, And Paths For Resolution, Adam M. Hasler

Graduate Masters Theses

This thesis investigates the relationship between macroscopic rheological signals and underlying microscopic dynamics in complex fluids, specifically focusing on ”living polymers” within the cetyltrimethylammonium bromide (CTAB) and sodium salicylate (NaSal) surfactant system. The research addresses the inverse parameterization problem, demonstrating how bulk measurements like zero-shear viscosity can mask fundamentally different physical topologies, such as purely cylindrical, reptating micelles versus highly branched networks. Through the successful synthesis of viscoelastically ”degenerate” samples, the study utilizes an array of characterization techniques including frequency sweeps, Large Amplitude Oscillatory Shear (LAOS) to resolve these unique underlying states. Furthermore, the work explores further avenues of study …

Microrheological Characterization Of Collagen-I Extracellular Matrix Remodeling During Tr146 Tumor Spheroid Invasion And Ppix-Mediated Photodynamic Therapy, Himantha Dilshan Saldonge

Graduate Masters Theses

Oral squamous cell carcinoma (OSCC) invasion is strongly regulated by interactions between tumor cells and the surrounding extracellular matrix (ECM). However, localized ECM mechanical changes during tumor invasion and after photodynamic therapy (PDT) remain insufficiently understood. This study mainly investigated: time-dependent viscoelastic remodeling of collagen-I ECM during TR146 tumor cell invasion, visualization of time-dependent TR146 tumor cell invasion and post-PDT response using live/dead fluorescence imaging, and the direct effect of PpIX-mediated PDT on the viscoelastic properties of spheroid-free collagen-I ECM. Three-dimensional TR146 spheroids were generated using a non-adherent agarose-based method, surrounded by a basement-membrane-like Matrigel layer, and embedded in 3.0 …

Symmetry Breaking And Restoration In The Grasshopper Ising Model, Aradh Bisarya

Graduate Masters Theses

Distance-selective interactions in Ising systems give rise to a range of rich and unexpected phenomena. A notable example is the so-called Grasshopper Ising model, a conserved spin Ising model with interactions only between spins at a fixed distance. This model is the discrete version of the following mathematical problem: A grasshopper lands at a random point on a planar lawn of area one. It then makes one jump of fixed distance in a random direction. What lawn shape maximizes the probability that the grasshopper lands on the lawn after the jump? The solution to this problem, corresponding to the ground …

The Grasshopper's Journey To The Bloch Sphere, David Llamas

Graduate Doctoral Dissertations

The Grasshopper Problem asks a simple geometric question. A grasshopper lands on a lawn of fixed area and jumps a fixed distance in a random direction. What shape of lawn maximizes the probability that the grasshopper remains on the lawn after jumping? The jump rule is rotationally symmetric, but the best lawns do not have to be. This dissertation studies how that symmetry breaking occurs, maps the continuum problem to a novel constrained spin system, and uses the spherical Grasshopper Problem to compare quantum singlet correlations with classical local models.

For planar lawns, boundary-integral and perturbative calculations explain why the …

A Statistical Mechanics Approach To Reinforcement Learning, Jacob Adamczyk

Graduate Doctoral Dissertations

Reinforcement learning (RL), the study of optimal decision-making over long timescales in stochastic systems, has recently seen remarkable advances due in large part to the efforts of the deep learning community. RL has witnessed great success in solving problems in video games, robotics, biological control, and language modeling. However, a unified statistical mechanics framework to understand and develop the corresponding algorithms is lacking. To address this issue, we begin by showing that the reinforcement learning problem can be formulated and solved using the tools of statistical mechanics. Drawing on physical principles of free energy minimization and invariance, we address important …

Information Processing In Quantum Thermodynamic Systems, Shou-I Tang

Graduate Masters Theses

This thesis extends the classical autonomous Hamiltonian framework of information thermodynamics to the quantum regime. In this formulation, a composite system consisting of a principal system, a heat bath, a memory, and a work source is described by fully quantum, time-independent Hamiltonian dynamics. By introducing the quantum speed limit (QSL) for the system and memory subsystems, referred to as the Quantum Thermodynamic Speed Limit (QTSL), I establish a connection between the QTSL and Landauer’s principle. This relationship reveals the fundamental constraints on quantum information processing in terms of dynamics and energy costs during the evolution. Furthermore, I present an interpretation …

Generation Of Non-Maxwell-Boltzmann Energy Distributions During Thermalization Of Interacting Baths, Roberto Onofrio, Bala Sundaram

Data and Datasets

data associated with all the figures in the publication.

Dynamics Of Thermalization In Classical Three-Dimensional Many-Body Systems: Non-Maxwellian Distributions And The Role Of Anisotropic Trapping, Roberto Onofrio, Bala Sundaram

Data and Datasets

The physics of interacting baths is of interest in a variety of contexts, ranging from ultracold atoms to ionized gases. While many features can already be captured in a one-dimensional model, others are speci c to the situation of two or three-dimensional systems. In this paper, we focus on three-dimensional features of a model for thermalization between two baths that we have explored in earlier publications. In contrast to the one-dimensional situation we show that, enroute to thermalization, deviations from the Maxwell-Boltzmann energy distributions more akin to  -distributions are observed. In three dimensions, these can be seen in changes at …

Application Of Graphical Models In Protein-Protein Interactions And Dynamics, Amir Vajdi Hoojghan

Graduate Doctoral Dissertations

Every organism contains a few hundred to thousands of proteins. A protein is made of a sequence of molecular building blocks named amino acids. Amino acids will be referred to as residues. Every protein performs one or more functions in the cell. In order for a protein to do its job, it requires to bind properly to other partner proteins. Many genetic diseases such as cancer are caused by mutations (changes) of specific residues which cause disturbances in the functions of those proteins.

The problem of prediction of protein binding site is a crucial topic in computational biology. A protein …