This thesis focuses on pioneering a scalable route to fabricate quantum information devices based upon single InAs/InP quantum dots emitting in the telecommunications wavelength band around 1550 nm. Using metallic gates in combination with nanotemplate, site-selective epitaxy techniques, arrays of single quantum dots are produced and electrostatically tuned with a high degree of control over the electrical and optical properties of each individual quantum dot. Using metallic gates to apply local electric fields, the number of electrons within each quantum dot can be tuned and the nature of the optical recombination process controlled. Four electrostatic gates mounted along the sides of a square-based, pyramidal nanotemplate in combination with a flat metallic gate on the back of the InP substrate allow the application of electric fields in any direction across a single quantum dot. Using lateral fields provided by the metallic gates on the sidewalls of the pyramid and a vertical electric field able to control the charge state of the quantum dot, the exchange splitting of the exciton, trion and biexciton are measured as a function of gate voltage. A quadrupole electric field configuration is predicted to symmetrize the product of electron and hole wavefunctions within the dot, producing two degenerate exciton states from the two possible optical decay pathways of the biexciton. Building upon these capabilities, the anisotropic exchange splitting between the exciton states within the biexciton cascade is shown to be reversibly tuned through zero for the first time. We show direct control over the electron and hole wavefunction symmetry, thus enabling the entanglement of emitted photon pairs in asymmetric quantum dots. Optical spectroscopy of single InAs/InP quantum dots atop pyramidal nanotemplates in magnetic fields up to 28T is used to examine the dispersion of the s, p and d shell states. The g-factor and diamagnetic shift of the exciton and charged exciton states from over thirty single quantum dots are calculated from the spectra. The g-factor shows a generally linear dependence on dot emission energy, in agreement with previous work on this subject. A positive linear correlation between diamagnetic coefficient and g-factor is observed.

This thesis reports experimental observations of electric fields using Rydberg atoms, including dc field measurements near the surface of an atom chip, and demonstration of measurement techniques for ac fields far from the surface. Associated theoretical results are also presented, including Monte Carlo simulations of the decoherence of Rydberg states in electric field noise as well as an analytical calculation of the statistics of dc electric field inhomogeneity near polycrystalline metal surfaces. DC electric fields were measured near the heterogeneous metal and dielectric surface of an atom chip using optical spectroscopy on cold atoms released from the trapping potential. The fields were attributed to charges accumulating in the dielectric gaps between the wires on the chip surface. The field magnitude and direction depend on the details of the dc biasing of the chip wires, suggesting that fields may be minimized with appropriate biasing. Techniques to measure ac electric fields were demonstrated far from the chip surface, using the decay of a coherent superposition of two Rydberg states of cold atoms. We have used the decay of coherent Rabi oscillations to place some bounds on the magnitude and frequency dependence of ac field noise. The rate of decoherence of a superposition of two Rydberg states was calculated with Monte Carlo simulations. The states were assumed to have quadratic Stark shifts and the power spectrum of the electric field noise was assumed to have a power-law dependence of the form 1/f^κ. The decay is exponential at long times for both free evolution of the superposition and and Hahn spin-echo sequences with a π refocusing pulse applied to eliminate the effects of low-frequency field noise. This decay time may be used to calculate the magnitude of the field noise if κ is known. The dc field inhomogeneity near polycrystalline metal surfaces due to patch potentials on the surface has been calculated, and the rms field scales with distance to the surface as 1/z^2. For typical evaporated metal surfaces the magnitude of the rms field is comparable to the image field of an elementary charge near the surface.

We determine the energy spectrum of the baryons by treating each of them as a three-body system with the interacting forces coming from a set of two-body potentials that depend on both the distance between the quarks and the spin and orbital angular momentum coupling terms. We first review constraint dynamics for a relativistic two-body system in order to assemble the necessary two body framework for the three-body problem. We review the different types of covariant two-body interactions involved in constraint dynamics, including vector and scalar, and solve the problem of energy eigenstates using constraint dynamics. We use the Two Body Dirac equations of constraint dynamics derived by Crater and Van Alstine, matched with the quasipotential formalism of Todorov as the underlying two-body formalism. We then use the three-body constraint formalism of Sazdjian to integrate the three two-body equations into a single relativistically covariant three body equation for the bound state energies. The results are analyzed and compared to experiment using a best fit method and several different algorithms, including a gradient approach, and Monte Carlo method.

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This thesis investigates the coherent phase modulation of ultrashort pulses using vibrating hydrogen as a molecular medium. Self-phase modulation in a gas-filled hollow core capillary allows the generation of highpower few-cycle pulses in the NIR. Such pulses can be used to drive high harmonic generation (HHG) to deliver attosecond duration pulses in the extreme ultraviolet and soft X-ray spectral region. While reaching unrivalled pulse durations (down to 67 as), these sources have characteristically low efficiencies. The pump-probe spectroscopy community would greatly benefit from brighter short wavelength sources with sub-5 fs duration. In this work I apply Amplified RamaN Impulsive Excitation for Molecular Phase Modulation (ARNIEMPM), a multiple pulse scheme, to coherently prepare vibrating hydrogen molecules and exploit them for the phase modulation of ultrashort pulses. The preparation of the molecular motion is performed via impulsive stimulated Raman scattering and transient stimulated Raman scattering. The generated in-phase motion of molecules creates an oscillating optical polarizability in the medium which can be exploited by a probe pulse propagating through it, acting as a 125THz frequency phase modulator, the fastest among molecular media. This technique has the potential to provide bright, isolated subfemtosecond duration ultra-violet (UV) pulses via spectral broadening of broadband pulses. I experimentally investigate the preparation of the molecular motion against multiple experimental parameters. I then demonstrate the molecular phase modulation of ultrashort broadband probes in the near-infrared (NIR) and UV via a degenerate interferometric scheme. I used a waveguide to increase the interaction length of the process and reduce the energy requirements for the medium preparation. This allowed the use of a single laser system to generate all the required pulses, which are largely diverse in terms of wavelength, duration and power. Additionally, I present a novel technique named Attosecond Resolved Interferometric Electric-field Sampling (ARIES), which is capable of directly measuring the waveform of arbitrary pulses with attosecond resolution. This technique is based on high-harmonic generation (HHG) acting as a temporal gate for an applied secondary field, and tracking its electric field amplitude as a shift in the HHG cut-off frequency. I present experimental demonstration of a pulse waveform measurement by accurately retrieving a know inserted variation in dispersion and carrier-envelope-phase. A theoretical calculation of the technique applicability over a wide spectral range is also presented.

xv, 204 p. : ill. (some col.) A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / This thesis reports on progress made toward realizing strong cavity quantum electrodynamics coupling in a novel micro-cavity operating close to the hemispherical limit. Micro-cavities are ubiquitous wherever the aim is observing strong interactions in the low-energy limit. The cavity used in this work boasts a novel combination of properties. It utilizes a curved mirror with radius in the range of 40-60 µm that exhibits high reflectivity over a large solid angle and is capable of producing a diffraction limited mode waist in the approach to the hemispherical limit. This small waist implies a correspondingly small effective mode volume due to concentration of the field into a small transverse distance. The cavity assembled for this investigation possesses suitably low loss (suitably low linewidth) to observe vacuum Rabi splitting under suitable conditions. According to best estimates for the relevant system parameters, this system should be capable of displaying strong coupling. The dipole coupling strength, cavity loss and quantum dot dephasing rates are estimated to be, respectively, g = 35µeV, κ = 30µeV, and γ = 15µeV. A survey of two different distributed Bragg reflector (DBR) samples was carried out. Four different probe lasers were used to measure transmission spectra for the coupled cavity-QED system. The system initially failed to display strong coupling due to the available lasers being too far from the design wavelength of the spacer layer, corresponding to a loss of field strength at the location of the quantum dots. Unfortunately, the only available lasers capable of probing the design wavelength of the spacer layer had technical problems that prevented us from obtaining clean spectra. Both a Ti:Al 2 O 3 and a diode laser were used to measure transmission over the design wavelength range. The cavity used here has many promising features and should be capable of displaying strong coupling. It is believed that with a laser system centered at the design wavelength and possessing low enough linewidth and single-mode operation across a wide wavelength range strong coupling should be observable in this system. / Committee in charge: Hailin Wang, Chairperson, Physics; Michael Raymer, Advisor, Physics; Jens Noeckel, Member, Physics; Richard Taylor, Member, Physics; Andrew Marcus, Outside Member, Chemistry

<p> In this dissertation we study properties of superconformal field theories (SCFTs) that arise from a variety of constructions. We begin with an extended review of various techniques in supersymmetry that are relevant throughout the work. In Chapter 3, we discuss aspects of theories with superpotentials given by Arnold's <i>A,D,E</i> singularities, particularly the novelties that arise when the fields are matrices. We focus on four-dimensional <i> N</i> = 1 variants of supersymmetric QCD, with <i>U</i>(<i> N_c</i>) or <i>SU</i>(<i>N_c</i>) gauge group, <i>N_f</i> fundamental flavors, and adjoint matter fields <i>X</i> and <i>Y</i> appearing in <i> W_A,D,E</i>(<i>X,Y</i>) superpotentials. We explore these issues by considering various deformations of the <i>W_A,D,E</i> superpotentials, and the resulting RG flows and IR theories. In Chapter 4, we examine the infrared fixed points of four-dimensional <i> N</i> = 1 supersymmetric <i>SU</i>(2) gauge theory coupled to an adjoint and two fundamental chiral multiplets. We focus on a particular RG flow that leads to the <i>N</i> = 2 Argyres-Douglas theory <i> H</i>₀, and a further deformation to an <i>N</i> = 1 SCFT with low <i>a</i> central charge. Then for the latter half of the dissertation we turn our attention to 4d SCFTs that arise from compactifications of M5-branes. In Chapter 6, we field-theoretically construct 4d <i>N </i> = 1 quantum field theories by compactifying the 6d (2,0) theories on a Riemann surface with genus <i>g</i> and <i>n</i> punctures, where the normal bundle decomposes into a sum of two line bundles with possibly negative degrees <i>p</i> and <i>q</i>. In Chapter 7, we study the 't Hooft anomalies of the SCFTs that arise from these compactifications. In general there are two independent contributions to the anomalies: there is a bulk term obtained by integrating the anomaly polynomial of the world-volume theory on the M5-branes over the Riemann surface, and there is a set of contributions due to local data at the punctures. Using anomaly inflow in M-theory, we describe how this general structure arises for cases when the four-dimensional theories preserve <i>N</i> = 2 supersymmetry, and derive terms that account for the local data at the punctures.</p><p>

<p> Quantum computers will potentially outperform classical computers for certain applications by employing quantum states to store and process information. However, algorithms using quantum states are prone to errors through continuous decay, posing unique challenges to engineering a quantum system with enough quantum bits and sufficient controls to solve interesting problems. A promising platform for implementing quantum computers is that of circuit quantum electrodynamics (cQED) using superconducting qubits. Here, two energy levels of a resonant circuit endowed with a Josephson junction serve as the qubit, which is coupled to a microwave-frequency electromagnetic resonator. Modern quantum circuits are reaching size and complexity that puts extreme demands on input/output connections as well as selective isolation among internal elements. Continued progress will require adapting sophisticated 3D integration and RF packaging techniques found in today's high-density classical devices to the cQED platform. This novel technology will take the form of multilayer microwave integrated quantum circuits (MMIQCs), combining the superb coherence of three-dimensional structures with the advantages of lithographic integrated circuit fabrication. Several design and fabrication techniques are essential to this new physical architecture, notably micromachining, superconducting wafer bonding, and out-of-plane qubit coupling. This thesis explores these techniques and culminates in the design, fabrication, and measurement of a two-cavity/one-qubit MMIQC featuring qubit coupling to a superconducting micromachined cavity resonator in silicon wafers. Current prototypes are extensible to larger scale MMIQCs for scalable quantum information processing.</p><p>

Bell's inequalities impose an upper limit on correlations between measurements of two-photon states under the assumption that the photons play by a set of local rules rather than by quantum mechanics. Quantum theory and decades of experiments both violate this limit. Recent theoretical work in quantum foundations has demonstrated that a local realist model can explain the non-local correlations observed in experimental tests of Bell's inequality if the underlying probability distribution of the local hidden variable depends on the choice of measurement basis, or ``setting choice''. By using setting choices determined by astrophysical events in the distant past, it is possible to asymptotically guarantee that the setting choice is independent of local hidden variables which come into play around the time of the experiment, closing this ``freedom-of-choice'' loophole. Here, I report on a novel experimental test of Bell's inequality which addresses the freedom-of-choice assumption more conclusively than any other experiment to date. In this first experiment in Vienna, custom astronomical instrumentation allowed setting choices to be determined by photon emission events occurring six hundred years ago at Milky Way stars. For this experiment, I selected the stars used to maximize the extent over which any hidden influence needed to be coordinated. In addition, I characterized the group's custom instrumentation, allowing us to conclude a violation of local realism by $7$ and $11$ standard deviations. These results are published in Handsteiner et. al. (\textit{Phys. Rev. Lett.} 118:060401, 2017). I also describe my design, construction, and experimental characterization of a next-generation ``astronomical random number generator'', with improved capabilities and design choices that result in an improvement on the original instrumentation by an order of magnitude. Through the 1-meter telescope at the NASA/JPL Table Mountain Observatory, I observed and generated random bits from thirteen quasars with redshifts ranging from $z = 0.1-3.9$. With physical and information-theoretic analyses, I quantify the fraction of the generated bits which are predictable by a local realist mechanism, and identify two pairs of quasars suitable for use as extragalactic sources of randomness in the next cosmic Bell test. I also propose two additional applications of such a device. The first is an experimental realization of a delayed-choice quantum eraser experiment, enabling a foundational test of wave-particle complementarity. The second is a test of the Weak Equivalence Principle, using our instrument's sub-nanosecond time resolution to observe the Crab pulsar at optical and near-infrared wavelengths. Using my data from the Crab Pulsar, I report a bound on violations of Einstein's Weak Equivalence Principle complementary to recent results in the literature. Most of these results appear in Leung et. al. (arXiv:1706.02276, submitted to \textit{Physical Review X}).

This thesis presents the development of a selective-etch fabrication process to create sub-10 nanometre metallic gaps and the subsequent use of the gaps to study the electronics of nanocrystals and molecules. A complete picture of the success of the process required both examination by scanning electron microscopy as well as probing the current response to an applied bias at low temperature. The empty gaps were fully characterised before self-assembling 7 nm CdSe nanocrystals onto the metal with the help of linker molecules. The I-V characteristics of the empty gaps showed a reduction of the tunnelling barrier height from the expected value (~5.1 eV, the work function of Au) when the results were fitted to the Simmons tunnelling model for a metal-insulator-metal system. Results indicate that after the barrier height is surpassed, a transition from direct to field-effect (Fowler-Nordheim) tunnelling occurs. After CdSe assembly, the collected I-V characteristics of the system at 77 K showed varied results. Many devices displayed conductance peaks at low voltages comparable to the results of the shadow evaporation process for 4.2 nm nanocrystals (also documented in this thesis). Several devices revealed switching between multiples of fundamental curves, suggesting conduction through multiples of nanocrystals.