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.
Results
Showing 1 to 20 of 30 for “"Quantum Criticality"”.
-
Aspects of quantum criticality in itinerant electron ferromagnetic systems
… This thesis is mainly concerned with such quantum critical points and is an investigation into the various phenomena seen in the phase diagram of itinerant ferromagnetic systems. We apply a standard theory of itinerant quantum criticality to a quantum-critical end-point in a …
-
Exotic phases and quantum criticality in gapless correlated electron systems
… a gauge field, can be addressed. Thirdly, in a quantum spin liquid phase that is likely to be realized in certain organic Mott insulators. Here we show how such a phase can be accessed from a low energy description of a metal, without resorting to slave-particle constructions. Methodologically, …
-
Pairing symmetry, competing orders, and quantum criticality in iron based superconductors via London penetration depth measurements
… reaches a maximum. This may arise from quantum fluctuations associated with a quantum critical point buried beneath the superconducting dome.
-
Strongly correlated electron behavior in transition metal intermetallics: enhanced thermoelectricity and quantum criticality in FeGa₃ and superconductivity in NiBi₃
<p>TGa3 (T = Fe, Ru & Os) and RuIn3 are a class of isostructural intermetallic binary compounds with interesting physical and structural properties. These materials are non-magnetic, narrow band gap semiconductors with large n-type thermopower below room temperature. Chemical doping drastically …
-
Applied fractionalization : quantum phases and phase transitions of strongly interacting systems
… where elementary excitations in a phase carry quantum numbers that are fractions of that corresponding to an electron. Similarly, there is growing numerical evidence of the theoretical phenomena of 'deconfined quantum criticality', where quantum Berry phases lead to emergence of fractionalized …
-
Topics in gauge/gravity duality
… in our understanding of strongly interacting quantum field theories. Roughly speaking, the correspondence maps the degrees of freedom of a $d$-dimensional quantum field theory in the strong coupling regime to weakly coupled string theory (gravity or supergravity) on a $(d+1)$-dimensional …
-
Hybridized Criticality and Elementary Excitations in LiHoF4
… the magnetic properties of LiHoF<sub>4</sub>. Quantum criticality in rare earth ferromagnet LiHoF<sub>4</sub> is complicated by the presence of strong crystal field and hyperfine interactions resulting, e.g., in incomplete mode softening reported by Rønnow et al. We construct a systematic …
-
Search, Discovery, Synthesis and Characterization of Itinerant Magnets Composed of Non-magnetic Constituents
… magnetism, non-Fermi liquid behavior, and quantum criticality. Surprisingly, while many systems exhibit both local and itinerant magnetism, only two are known to contain no local moment ions: Sc3In and ZrZn2. Doping experiments on Sc3In were used to investigate the effects of both magnetic …
-
Electrical transport and superconductivity in doped quantum critical ferroelectrics
… transport and superconductivity in doped quantum critical ferroelectrics) presents the results of research into the electrical transport and superconductivity found in the neighbourhood of quantum phase transitions in carrier-doped ferroelectrics and paraelectrics. The materials of …
-
Big data, bigger magnets, and tiny high-temperature superconducting cuprates
… region and on its periphery there are non-ohmic, quantum critical, and phase competition behaviours. To explore and disentangle these various effects, many high-field measurements have been taken over a range of temperatures, magnetic fields, applied currents, and hole dopings. The main focus of …
-
Strongly correlated ultra-cold bosonic atoms in optical lattices
… matter physics is to study the origin of exotic quantum phases such as coexistent and inhomogeneous phases, quantum criticality, and secondary ordered phases close to quantum critical points. Exotic phenomena in strongly correlated systems occur due to competing complex interactions of spin, …
-
Pressure Induced Quantum Phase Transitions in Metallics Oxides and Pnictides
Quantum phase transitions occur as a result of competing ground states. The focus of the present work is to understand quantum criticality and its consequences when the competition is between insulating and metallic ground states. Metal-insulator transitions are studied by means of electronic …
-
Neutron Scattering Studies of Unusual Spin Structure and Local Correlation in Complex Oxides
… (e.g. Colossal Magnetoresistance (CMR), Quantum Criticality, and High Temperature Superconductivity), the complexity of the underlying physics, and the promise of technological applications. In this work, elastic and inelastic neutron scattering is used to study two prototypes of CEMs: …
-
Unconventional Superconductivity in Uranium Ditelluride
… in this dissertation is the discovery of a quantum critical line in the Ha-Hb-Hc Cartesian field space. UTe2 undergoes a metamagnetic transition in which a large field along the b-axis is applied. Application of transverse field components along the a-axis and c-axis was found to suppress …
-
Non-perturbative approaches to strongly correlated electron systems
… field theory is dual to a d+1 dimensional quantum gravitational theory. Problems in strongly coupled field theory then have an equivalent description using weakly interacting gravitational theory, allowing a non-perturbative analysis. Chapter 1 will serve as an introduction. We will review …
-
Quantum Critical Ferroelectricity and Emergent Phenomena in KTaO3 and SrTiO3
This thesis explores the quantum phase diagrams of KTaO3 and SrTiO3, both quantum paraelectrics near to a ferroelectric quantum critical point, including study of material properties which may be influenced by proximity to a ferroelectric quantum phase transition. A quantum critical phase …
-
Generating and protecting high fidelity multi-particle entangled states with atom-photon interactions
… interactions to produce multi-particle quantum states of atoms. After reviewing the basic challenges associated with engineering atomphoton interactions and techniques for overcoming these, we first describe “counter-factual” carving, a new method that harnesses curious properties of …
-
Quantum critical matter: Casimir pairing, emergent orders and topological defects
… critical phenomena in two- and three dimensional quantum materials. Specifically we consider high temperature superconductors, dimerized quantum magnets and frustrated magnets. First, motivated by the recent discovery of a magnetic quantum critical point in hole-doped cuprates, we study the …
-
An Investigation of the Magnetic and Electrical Properties of YNi3
… behaviour and allow us to probe the quantum nature of the solid state in magnetic materials. Spin fluctuation theory is currentlythe most successful tool we have for trying to describe critical behaviour on the border of magnetism, and these materials are particularly suited to such …
-
Pressure Tuned Magnetism in d- and f-Electron Materials
Quantum phase transitions (QPT) on the border of magnetism have provided a fertile hunting ground for the discovery of new states of matter, for example; the marginal Fermi Liquid and non Fermi Liquid states as well high T$_C$ cuprate and magnetically mediated superconductivity. In this thesis I …
Page 1 of 2