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 11 of 11 for “"Critical fluctuations"”.
-
Aspects of quantum criticality in itinerant electron ferromagnetic systems
… 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 three-dimensional …
-
Superfluid Density Measurements of High-Temperature Superconducting Films
… close to the Tc, the superfluid density exhibits critical phase fluctuations described by an XY model. These phase fluctuations are compared to a model of the pseudogap described by preformed pairs. In contrast to previous reports on YBCO films, we find that the phase transition in a YBCO film is …
-
Hydrogen in niobium-tantalum superlattices
… phase transition was observed where critical fluctuations exist only for wavelengths longer than the superlattice periodicity. The absence of short wavelength fluctuations prohibit phase separation and constitutes a· novel manifestation of a coherent phase transition. A mean field …
-
Light scattering from tantalum diselenide
… frequency. This indicates the presence of critical fluctuations or mode coupling. A depolarized central peak is observed in close-in Raman scattering both with and without an iodine vapor cell filter. The intensity and width of this central peak both reach a maximum value at a temperature …
-
Quantum Tuning and Emergent Phases in Charge and Spin Ordered Materials
… in the proximity of a ferroelectric quantum critical point. This work presents the first high-precision dielectric measurements under hydrostatic pressure carried out on a quantum critical ferroelectric, leading to a full pressure-temperature phase diagram for SrTiO$_3$. The influence of …
-
Quantum critical matter: Casimir pairing, emergent orders and topological defects
In this thesis we address a few problems on 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 …
-
Superconductivity in the proximity of a quantum critical point
… tuned transition does not correspond to a true critical point, whilst the high pressure region may be occupied by an antiferromagnetic phase, with the true critical point at higher pressures. However, other interesting features emerge in the electrical resistivity and AC-susceptibility, along …
-
Coherent Terahertz Control and Ultrafast Spectroscopy of Layered Antiferromagnets
… in the van der Waals antiferromagnet FePS₃. Critical fluctuations near the phase transition are found to enhance both the magnitude and the lifetime of this new state. Additionally, a broadband two-dimensional (2D) THz spectroscopy technique is developed and employed to study interactions …
-
Fluctuations, Phase Separation and Wetting Films near Liquid-Gas Critical Point
… the study of the properties of pure fluids near critical point because they become stratified under their own weight. Near the critical point, all thermodynamic properties either diverge or converge and the heating and cooling cause instabilities of the convective flow as a consequence of the …
-
Seismic precursor identification method integrating acoustic emission physical models and multi-source data
… foundation, adopts the novel Method of Critical Fluctuations-Based (MCF-B) analysis as the core approach, and leverages AE technique to conduct cross-scale precursor identification research spanning laboratory experiments and field measurements, while integrating multi-source data and …
-
Quasi-condensation in low-dimensional Bose gases
… Since long-rang order is destroyed by infra-red fluctuations in one dimension, only the formation of a quasi-condensate is possible, which exhibits suppressed density fluctuations, but whose phase fluctuates strongly. It is shown that modified mean-field theories based on a symmetry-breaking …