CAREER: Quantum Dynamics and Topology in Low Dimensional Systems

University Of Pittsburgh, Pittsburgh PA

Investigators

Abstract

NONTECHNICAL SUMMARY This CAREER award supports research and education on condensed matter systems that exhibit quantum mechanical behavior beyond the microscopic regime. Quantum mechanics lies at the foundation of many existing and emerging technologies. For example, computers, cell phones, and medical imaging devices, all have critical components that operate on quantum technology. In fact, the General Conference on Weights and Measures has recently adopted a standard of mass (i.e., the kilogram) that is based on principles of quantum mechanics. This project aims to develop and study a wide collection of quantum phenomena that may be used in the next step of the quantum revolution. While the world we live in is governed by quantum mechanics at the fundamental level, most macroscopic objects appear "classical" because quantum effects are often washed out at large distances. The goal of this project is to study how quantum behavior can survive beyond the microscopic regime. The PI and his team will look for ways in which fundamental particles, such as electrons, can be bound together similarly to how atoms form molecules. Conversely, the PI will also seek ways in which electrons can fractionalize, i.e., behave collectively as if they were split up into multiple particles. Crucial to this research is understanding how particles interact with one another. A critical component to the success of quantum technology is the widespread literacy in quantum mechanics. Quantum concepts, notably superposition and entanglement, lie at the heart of all device applications and yet are poorly understood by students in Science, Technology, Engineering, and Mathematics (STEM). The PI will develop and test self-guided tutorials that could be used to complement standard undergraduate/graduate education in physics to include quantum concepts. Once validated, these tutorials can be widely disseminated and used in STEM education. Ultimately, this project seeks to promote awareness and deeper understanding of quantum phenomena. TECHNICAL SUMMARY This CAREER award supports research and education on condensed matter systems that exhibit quantum mechanical behavior and phenomenology beyond the microscopic regime. While the world we live in is governed by quantum mechanics at the fundamental level, most macroscopic objects appear "classical" because quantum effects are often washed out at large distances. For example, although the origin of ferromagnetism is quantum mechanical at the microscopic level, the phenomenology of magnets is well described via classical electromagnetism. The focus of this research is the study of effects that are macroscopically quantum, defying any effective classical description. Examples thereof include fractionalization, deconfined criticality, and many-body localization. The commonality shared by these effects is that they involve quantum dynamics and/or topology within strongly-interacting systems. The proposed research combines both analytical and numerical methods, to study quantum phenomena in a variety of theoretical models and experimental settings. The activities and goals of this proposal include: 1) Exploring the formation of composite excitations (such as pairs, trions, and tetrons) in low-dimensional systems, 2) Developing and testing algorithms that can simulate quantum dynamics, in order to study effects such as thermalization and localization in driven systems, 3) Finding new ways to extract topological invariants, such as Hall conductivity, from the static correlations of a many-body disordered system. This project will also entail improving public education in quantum mechanics, preparing future engineers and scientists for research in the 21st century and meeting the growing demand for quantum technologists. The PI will develop, test, and implement, self-guided tutorials on quantum many-body physics suitable for undergraduates and graduates in STEM. The tutorials will help students grasp abstract concepts in quantum many-body systems (such as entanglement), and will be based on learning models that emphasize scaffolded learning, peer-instruction, and weaning. These will be self-contained modular units that can be used to supplement traditional lectures, or be employed in independent self-study. The evaluation of this program will be published and the tutorials will be made available publicly to allow for wide dissemination and implementation across all interested institutions. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.