Spring 2024

Dissertation Committee Chair: Brian Swingle, Victor Galitski

Committee:  

Maissam Barkeshli

Jay Sau

Jonathan Rosenberg (Dean’s representative)

Quantum ergodicity refers to the remarkable ability of quantum systems to explore their entire state space allowed by symmetry. Mechanisms for violating ergodicity are of fundamental interest in statistical and molecular physics and can offer novel insights into decoherence phenomena in complex molecular qubits.  I will discuss the recent experimental observation of ergodicity breaking in rapidly rotating C60 fullerene molecules as a function of rotational angular momentum [1].

Antiferromagnetic materials with microscopic behavior resembling that of the Fermi-Hubbard model are expected to host excitons, or bound electron-hole pairs. In order to investigate such behavior, we have optimized states of the t-J model in the single-particle-single-hole sector using the density matrix renormalization group (DMRG).

Abstract: Quantum computing hardware capabilities have grown tremendously over the past decade, as evidenced by demonstrations of both quantum advantage and error-corrected logical qubits.  These breakthroughs have been driven, in part, by advances in quantum characterization, verification, and validation (QCVV).  I will discuss how QCVV provides a hardware-agnostic framework for assessing the performance of quantum computers; I will describe in detail how specific QCVV protocols (such as gate set tomography and robust phase estimation) have been used to characterize and sig

Quantum simulation stands as an important application of quantum computing, offering insights into quantum many-body systems that are beyond the reach of classical computational methods. For many quantum simulation applications, accurate initial state preparation is typically the first step for subsequent computational processes. This dissertation specifically focuses on state preparation procedures for quantum states with chiral topological order, states that are notable for their robust edge modes and topological properties.

The intersection of quantum electrodynamics (QED) and density-functional theory (DFT) has opened up exciting opportunities in controlling quantum matter through light-matter coupling. This frontier, however, is beset with computational challenges, especially in the weak and strong coupling regimes. Building upon previous research, we present the results of nonperturbative QED functional in the long-wavelength limit, centered solely on the matter Hilbert space.

Abstract: TBA

Since the discovery of Shor’s factoring algorithm, there has been a sustained interest in finding more such examples of quantum advantage, that is, tasks where a quantum device can outperform its classical counterpart. While the universal, programmable quantum computers that can run Shor’s algorithm represent one direction in which to search for quantum advantage, they are certainly not the only one. In this dissertation, we study the theory of quantum advantage along two alternative avenues: sensing and simulation.

Quantum information science offers a remarkable promise: by thinking practically about how quantum systems can be put to work to solve computational and information processing tasks, we gain novel insights into the foundations of quantum theory and computer science. Or, conversely, by (re)considering the fundamental physical building blocks of computers and sensors, we enable new technologies, with major impacts for computational and experimental physics.

Topological band structures are well known to produce symmetry-protected chiral edge states which transport particles unidirectionally. These same effects can be harnessed in the frequency domain using a spin-1/2 system subject to periodic drives.