Degree Date: December, 2013
Prasenjit Dutt's picture
Prasenjit Dutt
R. Shankar

Strongly correlated quantum transport out-of-equilibrium
The revolutionary advances in nanotechnology have facilitated the precise control and manipulation of mesoscopic systems where quantum effects are pronounced. Typical experimental settings are capable of driving these systems far from equilibrium, where linear response theory is inadequate. We study transport through quantum-impurity systems in the regime of strong correlations and determine the effects of large temperature and potential gradients on its many-body physics. We introduce a... more
Merideth Frey's picture
Merideth Frey
Sean Barrett
Professor of Physics

Sarah Lawrence College

Using Novel Pulse Sequences for Magnetic Resonance Imaging of Phosphorus-31 in Hard and Soft Solids
Since its invention in 1973, magnetic resonance imaging (MRI) has become an invaluable tool for clinical medicine, fundamental biomedical research, the physical sciences, and engineering. The vast majority of all MRI studies, in medicine and beyond, detect only the signal from a single nuclear isotope, H-1, in liquid water. Extending the reach of MRI to the study of other elements, and to hard or soft solids, opens new frontiers of discovery. In practice, however, the slower motion of the... more
Kurtis Geerlings's picture
Kurtis Geerlings
Michel Devoret
Research Manager

Gentex Corporation

Improving Coherence of Superconducting Qubits and Resonators
Superconducting qubits and resonators with quality factors exceeding 10^7 are of great interest for quantum information processing applications. The improvement of present devices necessarily involves the consideration of participation ratios, which budget the influence of each physical component in the total energy decay rate. Experiments on compact resonators in which participation ratios were varied has demonstrated the validity of this method, yielding a two-fold improvement in quality... more
Aaron Mertz's picture
Aaron Mertz
Eric Dufresne
Director, Science & Society Program

Aspen Institute

Collective Mechanics of Epithelial Cells
Cell–cell and cell–matrix adhesions play essential roles in the function of tissues, yet little is known about how crosstalk between these two adhesion types regulate cells' material properties and active processes. This dissertation combines experiment and theory to reveal how colonies of cells apply forces to the extracellular matrix. Using traction force microscopy, we measure forces transmitted to the substrate by colonies of epithelial cells with strong and weak cadherin-... more
Konstantin Nesterov's picture
Konstantin Nesterov
Yoram Alhassid
postdoctoral research associate

University of Wisconsin-Madison

Mesoscopic Effects in Chaotic Metallic Nanoparticles
We study electron interactions in a nanosized chaotic metallic grain with a large Thouless conductance. We use the so-called universal Hamiltonian, which describes the low-energy physics of such a grain. The noninteracting part of this model fluctuates and is described by random-matrix theory, while its interaction terms are universal and do not fluctuate. Of particular interest are grains in the fluctuation-dominated regime of pairing correlations, where the grain is so small that its single-... more
Alice Ohlson's picture
Alice Ohlson
John Harris

Investigating Parton Energy Loss with Jet-hadron Correlations and Jet vn at STAR
A strongly-coupled, deconfined state of quarks and gluons, known as the Quark-Gluon Plasma (QGP), is created in high-energy collisions of heavy nuclei. The QGP can be probed by high-momentum quarks and gluons (collectively known as partons) that are produced in hard scatterings early in the collision. The partons traverse the QGP and fragment into collimated "jets" of hadrons. Studies of parton energy loss within the QGP, or medium-induced jet quenching, can lead to insights into the... more
Kinga Partyka's picture
Kinga Partyka
Bonnie Fleming

Exclusive Muon-Neutrino Charged Current mu+Np topologies in ArgoNeuT
Neutrinos remain among the least understood fundamental particles even after decades of study. As we enter the precision era of neutrino measurements bigger and more sophisticated detectors have emerged. The leading candidate among them is a Liquid Argon Time Projection Chamber (LArTPC) detector technology due to its bubble-like chamber imaging, superb background rejection and scalability. It is a perfect candidate that will aim to answer the remaining questions of the nature of neutrino and... more
William Pontius's picture
William Pontius
Thierry Emonet

The Molecular Origins and Functional Role of Noise in a Simple Sensory Network
Biological pathways perform calculations with often-small numbers of constituent molecules, leading to potentially significant variability in their output. In this thesis, I use the chemotaxis pathway of the bacterium Escherichia coli as a model to investigate the molecular origins of large temporal fluctuations and their consequences for cellular behavior. The bacterial chemotaxis pathway is a simple sensory network that performs temporal comparisons of external chemical stimuli, enabling the... more
Matthew Reed's picture
Matthew Reed
Robert Schoelkopf
Research Staff Physicist

HRL Laboratories

Entanglement and Quantum Error Correction with Superconducting Qubits
A quantum computer will use the properties of quantum physics to solve certain computational problems much faster than otherwise possible. One promising potential implementation is to use superconducting quantum bits in the circuit quantum electrodynamics (cQED) architecture. There, the low energy states of a nonlinear electronic oscillator are isolated and addressed as a qubit. These qubits are capacitively coupled to the modes of a microwave-frequency transmission line resonator which serves... more
Charles Riley's picture
Charles Riley
Jack Sandweiss
Manager, Finance & Strategy

ConnectGen LLC

Searching for Local Parity Violation in Heavy Ion Collisions
Parity violation of the strong interaction is prohibited globally, however, it may be possible for parity to be violated locally in hot, dense, and deconfined QCD matter created in heavy ion collisions. Microscopic parity-odd domains in QCD are the consequence of topologically non-trivial configurations of gauge fields, and may be observable in heavy ion collisions due to the so called Chiral Magnetic Effect (CME). The CME predicts that provided a strong magnetic field (produced in a non-... more
Flavius Schackert's picture
Flavius Schackert
Michel Devoret
Software Engineer, Machine Learning

A Practical Quantum-Limited Parametric Amplifier Based on the Josephson Ring Modulator
This dissertation has addressed the problem of developing the Josephson Parametric Converter (JPC) as a practical phase-preserving microwave parametric amplifier operating at the quantum limit of added noise. The device consists of two superconducting resonators coupled through the Josephson Ring Modulator (JRM), which in essence consists of a loop of four identical Josephson tunnel junctions, threaded by an applied magnetic flux. The nonlinearity of the JRM is of the tri-linear form XYZ... more
Adam Sears's picture
Adam Sears
Robert Schoelkopf

Extending Coherence of Superconducting Qubits: from microseconds to milliseconds
Circuit quantum electrodynamics (Circuit QED) is the extremely successful framework for studying quantum devices developed along with the transmon, a superconducting charge qubit with an insensitivity to several types of dephasing. It involves the description of superconducting qubits and harmonic oscillators as quantized circuits. This thesis describes the implementation of two experiments that reduce circuit QED to its simplest components. Both experiments utilize elements that are known to... more
Degree Date: May, 2013
Sourpouhi Bedikian's picture
Sourpouhi Bedikian
Sarah Demers

A Search for the Charged Higgs: Using Tau Polarimetry with Proton-Proton Collisions at the ATLAS Detector
A search for a 130 GeV charged Higgs boson in ttbar events containing a tau lepton is presented. Tau polarimetry is used in order to distinguish the signal, t → H±b → τνb, from the dominant Standard Model background, t → W±b → τνb. The signal extraction is performed by a log-likelihood template fit. The dataset corresponds to an integrated luminosity of 4.6 fb^−1 of sqrt(s)=7 TeV proton-proton collisions collected with the ATLAS detector in... more
Christopher Gilbreth's picture
Christopher Gilbreth
Yoram Alhassid
Sr. Advanced Physicist

Honeywell Quantum Solutions

Ultracold Fermi Gases: Effective Interactions and Superfluidity
Cold atomic Fermi gases are clean, highly experimentally tunable systems with connections to many different fields of physics. However, in the strongly-interacting regime they are nonperturbative and difficult to study theoretically. One challenge is to calculate the energy spectra of few-body cold atom systems along the crossover from a gas described by a Bose-Einstein condensate (BEC) to a gas described by Bardeen-Cooper-Schrieffer (BCS) theory. The configuration-interaction (CI) method is... more
Archana Kamal's picture
Archana Kamal
Michel Devoret
Assistant Professor

Universty of Massachusetts Lowell

Nonreciprocity in active Josephson junction circuits
I will present different flavors of nonreciprocal photon dynamics realized using active parametric circuits based on Josephson junctions. The motivation stems from developing non-magnetic alternatives to existing nonreciprocal devices, invariably employing magnetic materials and fields and hence limited in their application potential for use with on-chip microwave superconducting circuits. The main idea rests on the fact the “pump” wave (or the carrier) in an active nonlinear system... more