Degree Date: May, 2020
Raymond Ehlers's picture
Raymond Ehlers
Helen Caines
Postdoctoral Associate

Oak Ridge National Lab

Jet-Hadron Correlations Measured in Pb--Pb Collisions at $\sqrt{s_{\text{NN}}} = 5.02$ TeV with ALICE
Quantum Chromodrynamics (QCD) describes the interactions of quarks and gluons. Due to asymptotic freedom, sufficiently high energy density can cause matter to transition to a deconfined state of matter known as the Quark-Gluon Plasma. As partons propagate through this QCD medium, which can be formed in ultra-relativistic heavy-ion collisions, they lose energy and the resulting jets are known to be modified in a phenomena known as jet quenching. This thesis investigates potential path length... more
Luyao Jiang's picture
Luyao Jiang
Jack Harris

Wells Fargo

Nonreciprocal dynamics in a cryogenic optomechanical system
Nonreciprocity in various branches of physics has been studied for more than a century, e.g., from classical to quantum mechanics, and from particle to condensed matter. It is particularly interesting to consider nonreciprocal phenomenon in open (non-hermitian) systems. In this dissertation, I use a cryogenic cavity optomechanical system to demonstrate robust nonreciprocal interactions between two phononic resonators. The nonreciprocity, either transient or static, is realized via the cavity... more
Norman Lam's picture
Norman Lam
John Murray
Postdoctoral Associate


Inhibitory Regulation of Cognitive Functions in Cortical and Thalamic Circuits: Computational Mechanisms and Experimental Predictions
Cognitive behaviors fundamentally arise from the interactions of numerous neurons in the brain. However, while neuronal properties are well-characterized, how an ensemble of interconnected neurons acts is generally not apparent from the single-neuron dynamics. Computation in specific circuits of neuronal populations is known to reflect key variables in core cognitive functions, such as decision making, although the underlying mechanisms are not fully understood. There thus are explanatory gaps... more
Claudia Lau's picture
Claudia Lau
Charles Ahn

Structural characterization of epitaxial oxide heterostructures via X-ray scattering
The impact of atomic-scale structural distortions on the transport properties of epitaxial thin film oxides and their interfaces is investigated through high resolution surface x-ray diffraction. The crystalline thin films studied are the metallic oxides (La,Sr)TiO3 and LaNiO3, the high mobility oxide BaSnO3, the high dielectric oxide LaInO3, and the ferroelectric oxide Pb(Zr,Ti)O3. Films were grown on SrTiO3 and DyScO3 commercial substrates by the physical vapor deposition techniques off-axis... more
Catherine Matulis's picture
Catherine Matulis
Damon Clark


Contrast adaptation in Drosophila direction-selective circuits
In visual systems, neurons adapt both to the mean light level and to the range of light levels, or the contrast. Contrast adaptation has been studied extensively, but it remains unclear how it is distributed among neurons in connected circuits, and how early adaptation affects subsequent computations. In this study, we investigated temporal contrast adaptation in neurons across Drosophila's visual motion circuitry. Several ON-pathway neurons showed strong adaptation to changes in contrast... more
Shantanu Mundhada's picture
Shantanu Mundhada
Michel Devoret
Quantum Engineer

Quantum Circuit, Inc.

Hardware-efficient autonomous quantum error correction
The promise of quantum speedup in information processing is not yet fulfilled in a useful quantum algorithm due to the susceptibility of quantum information to decoherence. This makes quantum error correction (QEC) a vital area of research. The vast majority of QEC protocols, however, come with an overwhelming hardware and software overhead. For superconducting quantum circuits, it is possible to minimize this overhead by hardware-efficient encoding in infinite dimensional Hilbert spaces of... more
Kyungjoo Noh's picture
Kyungjoo Noh
Liang Jiang
Quantum Research Scientist

Amazon Web Services

Quantum computation and communication in bosonic systems
Quantum computation and communication are important branches of quantum information science. However, noise in realistic quantum devices fundamentally limits the utility of these quantum technologies. A conventional approach towards large-scale and fault-tolerant quantum information processing is to use multi-qubit quantum error correction (QEC), that is, to encode a logical quantum bit (or a logical qubit) redundantly over many physical qubits such that the redundancy can be used to detect... more
Brooke Russell's picture
Brooke Russell
Bonnie Fleming
Owen Chamberlain Postdoctoral Fellow

Lawrence Berkeley National Laboratory

An Electron Neutrino Appearance Search in MicroBooNE with 5$\times$10$^{19}$ POT
MicroBooNE is a single-phase liquid argon time projection chamber (LArTPC) short-baseline accelerator neutrino experiment located at Fermi National Accelerator Laboratory in the Booster Neutrino Beam. MicroBooNE's foremost scientific objective is to definitively resolve the low-energy excess of single shower electromagnetic events seen by the precursor MiniBooNE experiment. This thesis examines a small fraction of early MicroBooNE data. By leveraging fine-grained drifted ionization... more
Kyle VanderWerf's picture
Kyle VanderWerf
Corey O'Hern

Geometry and Contact Mechanics of Athermal Jammed Packings of Frictionless Spherical and Nonspherical Particles
I perform computational studies of quasistatically jammed packings of frictionless particles of a variety of shapes. Each of the four studies presented in this dissertation focuses primarily on the connection between the mechanical and geometric properties of these packings – specifically, how physical aspects such as force and torque balance, pressure, and shear and bulk moduli correlate with (a) constituent particle shape, (b) the degree of particle ordering in packings, and (c) the... more
Shilo Xia's picture
Shilo Xia
David C. Moore
Chamberlain Fellow


Search for Neutrinoless Double Beta Decay and Detector Physics Measurements with the Final EXO-200 Dataset
Liquid xenon (LXe) is employed in a number of current and future detectors for rare event searches. This work presents the latest results from the EXO-200 experiment, which searched for neutrinoless double beta decay (0$\nu\beta\beta$) in $^{136}$Xe between 2011 and 2018. With upgraded hardware, increased exposure and analysis improvements, the detector resolution, sensitivity and final data limit were also improved over time. Taking advantage of a single-phase, large detector with good purity... more
Degree Date: December, 2019
Tonima Tasnim Ananna's picture
Tonima Tasnim Ananna
Meg Urry
Postdoctoral Associate

Dartmouth College

A new X-ray population synthesis model, its physical implications, along with detailed analysis of AGN X-ray spectral parameter space are presented in this work. This population synthesis model uniquely fits all the newest observed constraints from high energy X-ray bands such as NuSTAR and Swift-BAT, and predicts a Compton-thick fraction of 50−56% in the local Universe. The new X-ray population synthesis model was computed using a neural network. Given an input distribution of AGN... more
Charles Brown's picture
Charles Brown
Jack Harris
Postdoctoral Associate

University of California, Berkeley

Optical, Mechanical and Thermal Properties of Superfluid Liquid Helium Drops Magnetically-Levitated in Vacuum
The field of optomechanics studies the interactions between light and the motion of an object. One of the goals in this field is to generate and control highly non-classical motion of a massive mechanical oscillator. There has been progress in generating such non-classical motion via coupling the oscillator to a qubit, or by utilizing the non-linearity of single photon detection. However, interest still remains in generating non-classical motion directly via the optomechanical interaction... more
James Ingoldby's picture
James Ingoldby
Thomas Appelquist
Postdoctoral Researcher

ICTP in Trieste Italy

EFTs for Nearly Conformal Gauge Theories
The phenomena of electricity and magnetism, beta decay in radioactive nuclei, and the confinement of quarks within the proton can each be explained using the three different gauge theories which collectively make up the standard model. Alternative gauge theories display new kinds of exotic phenomena, which are not fully understood. For example, if the field content is chosen appropriately, a gauge theory is said to be in the conformal window, and can acquire conformal symmetry. In this case,... more
Prashanta Kharel's picture
Prashanta Kharel
Peter Rakich
Device Lead and Founding Team Member

Hyperlight Corporation

Utilizing Brillouin Interactions for Optical Control of Bulk Acoustic Waves.
The interaction between light and mechanical motion has been harnessed for a variety of scientific and technological applications ranging from studies of decoherence to precision metrology and quantum information.  Building on these accomplishments, optomechanical systems show great potential for various classical and quantum applications, including ultra-low-noise oscillators and high-power lasers to quantum transducers and quantum memories. Central to these goals of optomechanics, and... more
Stefan Krastanov's picture
Stefan Krastanov
Liang Jiang
Postdoctoral Associate


New Approaches to Control, Calibration, and Optimization of Quantum Hardware
In this dissertation I present a number of techniques that form building blocks for the quantum manipulations spanning various levels of the quantum technology stack. We begin at the very bottom, with techniques for the universal control of a quantum harmonic oscillators. Oscillators like microwave and optical cavities are among some of the more promising physical systems on top of which to implement quantum logic. However, most of our technology until recently has been focused on manipulating... more