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 42 for “"Fermi gas"”.
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A new degenerate Fermi gas apparatus
… a new research direction of studying degenerate fermionic Lithium atoms in optical lattices. The major contributions to the new experimental setup are the Lithium laser system, a new imaging technique, and an advanced experiment control system. First, a tapered amplifier laser diode system is …
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Ultracold Fermi gas with repulsive interactions
… results from experiments of ultracold atomic Fermi gases with repulsive interaction. Itinerant ferromagnetism was studied by simulating the Stoner model with a strongly interacting Fermi gas of ultracold atoms. We observed nonmonotonic behavior of lifetime, kinetic energy, and size for …
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Geometric Squeezing of a Degenerate Fermi Gas
Quantum simulation with ultracold gases provides a highly customizable platform for the study of many-body physics, shedding new light on important physical systems. Magnetic fields or, equivalently in the case of a uniform, static field, rotation are especially important parameters for many-body …
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Universal quantum viscosity in a unitary Fermi gas.
Unitary Fermi gases, first observed by our group in 2002, have been widely studied as they provide model systems for tabletop research on a variety of strongly coupled systems, including the high temperature superconductors, quark-gluon plasmas and neutron stars. A two component6Li unitary Fermi …
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High-temperature superfluidity in an ultracold Fermi gas
… experiments in which a strongly interacting gas of fermions was brought into the superfluid regime. The strong interactions are induced by a Feshbach scattering resonance that allows to tune the interfermion scattering length via an external magnetic field. When a Fermi mixture was cooled on …
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Thermodynamics and solitonic excitations of a strongly-interacting Fermi gas
… solitonic excitations of a strongly-interacting Fermi gas, realized with 6Li atoms at a Feshbach resonance where the scattering length is large. The strongly-interacting Fermi gas, also called the unitary Fermi gas, exhibits a novel superfluidity that is a crossover of the Bose-Einstein …
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Quasi-particle Breakdown and Heat Transport in a Homogeneous Strongly-interacting Fermi Gas
… on a homogeneous strongly-interacting Fermi gas, consisting of a spin mixture of ⁶Li atoms with interactions induced by a Feshbach resonance. The tunability and universality of this atomic gas make it an ideal platform to study many-body physics of interacting Fermi systems. The …
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The existence of singular terms and their effects on the validity of Fermi liquid theory in two dimensions
The question of the breakdown of Fermi liquid theory in two dimensions is examined in the context of perturbation theory for a dilute interacting Fermi gas. The quasiparticle interaction function, fic;u;, is calculated for such a system. The interaction function, calculated to second order in terms …
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Thermodynamic and hydrodynamic behaviour of interacting Fermi gases
Fermionic matter is ubiquitous in nature, from the electrons in metals and semiconductors or the neutrons in the inner crust of neutron stars, to gases of fermionic atoms, like 40K or 6Li that can be created and studied under laboratory conditions. It is especially interesting to study these …
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Quantum transport in strongly interacting, ultracold fermi gases in box potentials
Transport of strongly interacting fermions is crucial for systems as varied as high-𝑇 subscript 𝑐 superconductors, twisted bi-layer graphene, nuclear fission, and neutron stars. In this thesis, I will describe the experiments we performed to measure the transport properties of a …
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Fluctuations and state preparation in quantum degenerate gases of sodium and lithium
… of spin and density fluctuations in degenerate Fermi gases. We begin by presenting a proof-of-principle experiment that demonstrates how information about atomic fluctuations can be extracted from experimental images and used to measure the temperature of a noninteracting system. We then …
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Strongly interacting Fermi gases : non-equilibrium dynamics and dimensional crossover
Experiments using ultracold atomic gases address fundamental problems in many-body physics. This thesis describes experiments on strongly-interacting gases of fermionic atoms, with a focus on non-equilibrium physics and dimensionality. One of the fundamental dissipative processes in two-component …
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Construction of a quantum gas microscope for fermionic atoms
… with ultracold atoms in optical lattices: the Fermi gas microscope. Improving upon similar designs for bosonic atoms, our Fermi gas microscope has the novel feature of being able to achieve single-site resolved imaging of fermionic atoms in an optical lattice; specifically, we use fermionic …
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Topics in many-body physics
… parts. The first describes a study of the dilute Fermi gas with short range repulsive interactions in 2D, with special emphasis on questions related to the validity of Fermi liquid theory. We find that despite the existence of non-perturbative effects due to two-dimensionality, namely linearly …
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Interacting fermions : a holographic approach/
… properties are usually described by Landau's Fermi liquid theory. That is, they behave more or less like a free Fermi gas, with a few modifications due to electron-electron interactions. However, there exist a few metallic materials whose phenomenology does not fit within Fermi liquid theory. …
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A study in spherical accretion of self-gravitating fluids in a general relativistic framework
… then focused on the accretion of a relativistic Fermi gas and the implications this might have on the rapid growth of supermassive black holes from clouds of sterile neutrino dark matter in the early universe. The results give good agreement with a Newtonian model of supermassive black hole …
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Fermi Mixtures: Effects of Engineered Confinements
… the theory of the normal state of the unitary Fermi gas at T = 0 and the main properties of the normal-to-superfluid transition. Then we study the trapped gas under adiabatic rotation, i.e., avoiding the formation of vortices. We show that for polarized systems the rotation enhances the …
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Heat capacity of dilute solutions of liquid He[superscript 3] in He[superscript 4] at low temperatures
… .005 K and .20 K, are characteristic of an ideal Fermi gas with m'l'< dependent only slightly on concentration. The solution with a molar concentration of Re3 of (1.32 ± .01)% had a degeneracy temperature of (.141 ± .002)oK and m*/m = 2.38 ±.04. For the solution with a (5.02 -+ .03)% concentration …
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Quantum liquid crystal phases and unconventional magnetism in electronic and atomic fermi systems
… crystal phases in metallic systems and itinerant Fermi systems with dipole-dipole interactions. It is based on published works of Refs. [65, 193, 68, 67, 66]. In the first part of the Thesis, I present the construction of a generalization of the the McMillan- de Gennes theory of nematic-smectic …
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