Alumni

Degree Date: May, 2016

William Smith
Corey O'Hern

Modeling Diffusion and Motion in Cells at the Molecular Level


Due to the complexity inherent in biological systems, many particles involved exhibit complicated spatiotemporal dynamics that go beyond the standard models of diffusion of molecules and dynamics of polymers. Here, we investigate two examples of this: the dynamics of intrinsically disordered proteins, and the diffusion of a probe particle in a bacterial cell. Intrinsically  disordered proteins (IDPs) are a class of proteins that do not possess well-defined three-dimensional  ... more
Degree Date: December, 2015

Jeffrey Ammon
David DeMille

Progress towards a measurement of nuclear-spin-dependent parity violation in diatomic molecules


Nuclear-spin-dependent parity violation (NSD-PV) effects arise from exchange of the Z boson between electrons and the nucleus, and from interaction of electrons with the nuclear anapole moment (a parity-odd magnetic moment induced by electroweak interactions within the nucleus).  These effects cause a mixing of opposite-parity levels in atoms and molecules, where the size of the mixing is inversely proportional to the energy difference of the mixed levels.  We study NSD-PV effects... more

Camille Avestruz
Daisuke Nagai

Modeling Galaxy Cluster Outskirts with Cosmological Simulations


The observational study of galaxy cluster outskirts is a new territory to probe the thermodynamic and chemical structure of the X-ray emitting intracluster medium (ICM) and the intergalactic medium (IGM). Cluster outskirts are particularly important for modeling the Sunyaev-Zel’dovich effect, which is sensitive to hot electrons at all radii and has been used to detect hundreds of galaxy clusters to high-redshift (z<1) with recent microwave cluster surveys such as ACT, Planck, and SPT.... more

Barry Bradlyn
Nicholas Read

Linear response and Berry curvature in two-dimensional topological phases


              In this thesis we examine the viscous and thermal transport properties of chiral topological phases, and their relationship to topological invariants. We start by developing a Kubo formalism for calculating the frequency dependent viscosity tensor of a general quantum system, both with and without a uniform external magnetic field. The importance of contact terms is emphasized. We apply this formalism to the study of... more

Faustin Carter
Daniel Prober

A transition-edge-sensor-based instrument for the measurement of individual He2* excimers in a superfluid 4He bath at 100 mK


This dissertation is an account of the first calorimetric detection of individual He2* excimers within a bath of superfluid 4He. When superfluid helium is subject to ionizing radiation, diatomic He molecules are created in both the singlet and triplet states. The singlet He2* molecules decay within nanoseconds, but due to a forbidden spin-flip the triplet molecules have a relatively long lifetime of 13 seconds in superfluid He. When He2* molecules decay, they emit a ~15 eV photon. Nearly all... more

Nathan Cooper
Volker Werner

Structure of A = 76 Nuclei and Fast-Timing Studies of the Rare-Earth Region


Photon strength of nuclei has been a topic of recent intrigue due to postulated exotic modes of excitation, such as a neutron skin resonance, as well as the difficulty of its measurement near the neutron separation energy. The large number of levels up to the neutron separation energy, a region of particular interest in the calculation of nuclear reaction probabilities, causes detailed and accurate measurements to be close to the threshold of current experimental limits. This talk will begin... more

Daniel Guest
Paul Tipton/Tobias Golling

A Search for Scalar Charm Quarks with the ATLAS Detector at the LHC


This thesis presents the results of a search for pair-produced scalar charm quarks with the ATLAS detector at the LHC. The search uses 20.3 fb^-1 of data collected during the sqrt(s) = 8 TeV 2012 run. Each charm quark decays to neutrilinos and charm quarks, resulting in a final state consisting of two charm jets and missing transverse energy. A novel `charm tagging' algorithm was developed to separate this signature from backgrounds, and is discussed in detail. As no evidence of physics... more

Eric Holland
Robert Schoelkopf

Cavity State Reservoir Engineering in Circuit Quantum Electrodynamics


Engineered quantum systems are poised to revolutionize information science in the near future. A persistent challenge in applied quantum technology is creating controllable, quantum interactions while preventing information loss to the environment, decoherence. In this thesis, we realize mesoscopic superconducting circuits whose macroscopic collective degrees of freedom, such as voltages and currents, behave quantum mechanically. We couple these mesoscopic devices to microwave cavities forming... more

Peter Koo
Simon Mochrie

Novel optical-based methods and analyses for elucidating cellular mechanics and dynamics


Resolving distinct biochemical interaction states by analyzing the diffusive behaviors of individual protein trajectories is challenging due to the limited statistics provided by short trajectories and experimental noise sources, which are intimately coupled into each protein’s localization. In the first part of this thesis defense, I will describe a novel, machine-learning based classification methodology, called perturbation expectation-maximization (pEM), which simultaneously analyzes... more

Daliang Li
Witold Skiba

Covariant Methods for Superconformal Field Theories


In this thesis, we develop manifestly covariant methods for 4 dimensional, N = 1 superconformal field theories. First, we generalize the embedding formalism in conformal field theories (CFTs) to N = 1 superconformal field theories (SCFTs). As applications we construct manifestly superconformally covariant expressions for 2- and 3-point correlation functions involving the supercurrent multiplet or the global symmetry current superfield. Next, we combine this superembedding formalism with the... more

Tudor Petrescu
Karyn Le Hur

Topological phases with ultracold atoms and photons


In the first part of the talk, we introduce two–dimensional lattice tight–binding models that realize the quantum anomalous Hall effect (QAHE). For a Kagome lattice whose degrees of freedom are photons in microwave resonators, we discuss protocols to access the local Berry curvature and the Chern number of Bloch bands from the semiclassical dynamics of wavepackets. We proceed to Haldane’s model for QAHE on the honeycomb lattice, but with repulsively interacting bosons at unit... more

Brian Vlastakis
Robert Schoelkopf

Controlling coherent state superpositions with superconducting circuits


Quantum computation requires a large yet controllable Hilbert space. While many implementations use discrete quantum variables such as the energy states of a two-level system to encode quantum information, continuous variables could allow access to a larger computational space while minimizing the amount of required hardware. With a toolset of conditional qubit-photon logic, we encode quantum information into the amplitude and phase of coherent state superpositions in a resonator, also known as... more
Degree Date: May, 2015

Tomas Aronsson
John Harris

Cross section of bottom electrons in proton-proton collisions in the ALICE experiment


High-energy heavy-ion collisions at the LHC allow for the study of the properties of the quark-gluon plasma (QGP). Heavy quarks, charm and bottom, produced in the initial hard scattering processes of the collision are excellent probes of the QGP. When heavy quarks traverse the QGP they are expected to lose energy and such energy loss is predicted to be smaller than for gluons and light quarks. On the other hand, recent experimental data indicate larger energy loss than expected. Heavy flavor... more

Hongchul Joseph Bae
Vincent Moncrief

Wormhole Solutions to the Bianchi IX Wheeler-DeWitt Equation using the Euclidean-signature Semi-classical Method


A Euclidean-signature semi-classical method is used to construct both ground and excited state solutions to the canonically quantized Bianchi IX (Mixmaster) cosmological models. Employing a modified form of the semi-classical ansatz, we solve the relevant Wheeler-DeWitt equation asymptotically by integrating a set of linear transport equations along the flow of a suitably chosen solution to the corresponding Euclidean-signature Hamilton-Jacobi equation. For the Moncrief-Ryan (or ‘wormhole... more

Alexander Cerjan
A. Douglas Stone

Fundamental physics and device design using the steady-state ab initio laser theory


In this thesis we generalize and extend the steady-state ab initio laser theory (SALT), first developed by Tureci and Stone, and apply it problems in laser design. SALT as first formulated modeled the gain medium as identical two-level atoms, leading to the well-known Maxwell Bloch laser equations. The result is a set of coupled non-linear wave equations that treats the openness of the cavity exactly and the non-linear modal interactions to infinite order. Most gain media have more than two... more