Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 28 for “"Edge modes"”.
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Soft Hair and Subregions in Quantum Gravity
… problem. More generally, they are known as ‘edge modes’, and play a key role in the structure of the quantum state. Another approach to black hole information involves entanglement, and a key theme of this thesis is to explore aspects of the relationship between edge modes and entanglement. …
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Linear and nonlinear edge dynamics and quasiparticle excitations in fractional quantum Hall systems
… discuss its basic features, such as the gapless edge modes and the gapped quasiparticle excitations in the bulk. We close this introductory part with a fourth chapter which presents a brief overview on the chiral Luttinger liquid theory. In the second part of this thesis we instead proceed to …
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Two classes of unconventional photonic crystals
… to the phenomenon of disorder-immune one-way edge modes. I describe a system in which time reversal symmetry is broken strongly enough for experimental observation of the one-way edge modes. In addition to numerical studies of this photonic crystal, I develop an analytical effective theory, …
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Nonlinear dissipative dynamics of optomechanical and laser arrays
… in the minimal setup composed of two optical modes with photon tunneling assisted by a mechanical self-oscillator. Employing the quantum van-der-Pol oscillator as the simplest dynamical model for a mechanical self-oscillator enables us to take quantum fluctuations into account using the …
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Analysis of Linear and Nonlinear Quasiperiodic Metamaterials with Local Resonators
… In the first part of this work, the topological edge modes are utilized to improve energy harvesting capabilities via the inclusion of electromechanical resonators. The resonators are modeled as a lumped parameter piezoelectric material shunted to a single resistor. Through eigenvalue and Chern …
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Twist angle physics in graphene based van der Waals heterostructures
… allowing us to put independent quantum Hall edge modes in both layers. We study the edge state interactions in this system, culminating in the formation of a quantum spin Hall state in twisted bilayer graphene. In the small twist angle limit, interlayer interactions are strong and the layers …
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Majorana-based Topological Quantum Algorithms in Magnet-Superconductor Hybrid Structures
Majorana zero modes harbored by topological superconductors may be the key ingredient for the realization of fault-tolerant quantum computing and topologically protected quantum devices. Magnet-superconductor hybrid (MSH) systems have proven to be an experimentally versatile platform for quantum …
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Phase transitions and symmetry breaking in disordered quantum Hall edge states
Tunneling into the edge of a quantum Hall droplet is a sensitive probe of the topological orders believed to exist in fractional quantum Hall states. The tunneling behavior of a general hierarchy state is studied within the chiral-Luttinger-liquid model of low-energy edge dynamics. Adding random …
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Chiral Phases on the Lattice
… which defines chiral field theories as the edge modes of chiral phases. We begin by reviewing the deep connections between chiral phases of matter, chiral field theories, and anomalies. We then develop numerical treatments of an 𝑆𝑈(2) chiral field theory, and provide a semiclassically …
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Hollow condensates, topological ladders and quasiperiodic chains
… and end by focusing on the physics of localized edge modes and topological phases in quasi-one-dimensional ladder models. For all three topics we maintain a focus on experimentally accessible, physically realistic systems and explicitly discuss experimental implementations of our work or its …
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Topological Signatures for the Kitaev Chain in and out of Equilibrium
… and the presence of topologically protected edge modes. Bulk topological invariants, such as the Zak phase and the winding number, are examined and shown to signal transitions between distinct gapped phases. A complementary perspective is also developed, based on non-local order parameters …
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Engineering topology and correlation in epitaxial thin film kagome metals
… magnetic instabilities and topological edge modes. We also demonstrate how the kagome spectrum reconstructs upon intense inter-kagome hybridization or broken crystallographic symmetry, eventually giving rise to new types of flat bands and their derived anomalies. To track the origins of …
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Photonics for technology : circuits, chip-scale LIDAR, and optical neural networks
… including topologically protected one-way modes, integrated photonic LIDAR, and optical neural networks. First, we numerically investigate large Chern numbers in photonic crystals and explore their origin from simultaneously gapping multiple band degeneracies. Following this, we perform …
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Majorana qubits in non-Abelian topological superconductors
… fermionic excitations even when gapless bosonic modes are present. Finally, we explore the non-perturbative effect of strong fluctuations of superconducting order parameter, when the mean-field description in terms of Bogoliubov quasiparticles is invalidated. We consider a model of two-leg ladder …
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Quantum transport in gapped graphene
… a spin-degenerate ballistic counter-propagating edge state forms and dominates with a possible secondary contribution from a network of one-dimensional conducting channels with soliton-like domain walls. The spin-degenerate ballistic edge states offer possibilities for electronic applications …
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Quantum spins in semiconductor nanostructures: Hyperfine interactions and optical control
… by lifting the topological protection of edge modes. I will present a model that allows for an analytical study of the effects of magnetic impurities within an experimental framework. It will be discussed how the same platform also enables a novel approach for applications of spintronics …
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Scanning tunneling microscopy and spectroscopy study of phase transitions and topology in layered transition metal dichalcogenides
… crystalline insulators and 1D topological edge states. The system hosts two types of step edges: odd steps with height equal to a half-integer multiple of the lattice constant, and even steps with height equal to an integer multiple of the lattice constant. It is known that the odd steps …
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Numerical methods of characterizing symmetry protected topological states in one dimension
… suppressed. The inversion symmetry restricts the edge modes of the system to be cooper-pairs other than two uncorrelated electrons. It is also proved by the 2 pi periodicity in the fractional Josephson effects. At last we apply machine learning methods for classification of SPT phases when strong …
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Engineering light-matter interaction using two dimensional materials
… derived from their coupled plasmon-phonon modes, leading to the appearance of tunable dips in the spontaneous emission spectra. Going beyond graphene, I consider a generic gapped Dirac system. I show that the valley imbalance due to pumping with a specific circular polarization, leads to a …
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Dynamical Aspects of Topological Quantum Systems
… properties of chiral and helical topological edge modes. We find that the decoherence rate of the former and the deviation from quantized conductivity of the latter are (not) exponentially suppressed in the inverse temperature when the phase in question is protected by unitary (antiunitary) …
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