Research

Below are brief descriptions of some of my research projects. For further details, visit the links or see my CV.

• Lévy processes and Extreme Events

Lévy processes are the continuous-time analog of random walks, and include the well-known Wiener process (i.e. Brownian motion) as well as the $\alpha$-stable processes, where the stochastic increment is drawn from a power-law distribution. These $\alpha$-stable Lévy processes are important for modeling a variety of extreme events (geologic processes, market crashes), as well as systems exhibiting anomalous diffusion (laser-cooled atoms, certain animal foraging behavior). My recent research has focused on conditioned Lévy processes, or Lévy bridges, which are a powerful tool for analyzing the history of a Lévy process. One of my recent results shows that by considering Lévy bridges, it is possible to derive a useful length scale which has applications for the detection of extreme events, as well as giving insight into the behavior of Lévy processes.

• Full paper (arXiv)
• PhD Dissertation (pdf)
• Detecting extreme events
• Visualizing Lévy self-similarity

• Anomalous Diffusion and Laser Cooled Atoms

Laser-cooled atoms are essential for a variety of high precision experiments, such as the development of Bose-Einstein condensates, atomic clocks, and a variety of precision metrology. Beyond direct applications, cold atoms themselves are an interesting testing ground for stochastic transport, as they are isolated systems with well defined forces. For part of my graduate research, I studied anomalous diffusion in Sisyphus cooling, and how certain boundary crossing statistics can have strong signatures indicating the presence of anomalous diffusion and Lévy flights.

• DAMOP Talk
• PhD Dissertation (pdf)

• Experiments with a Single Neutral Atom

As part of my graduate research, I performed a number of experiments and simulations with a single trapped rubidium atom. These included developing control systems for automatically trapping, manipulating, and monitoring single atoms (e.g. real-time imaging of a single trapped atom), as well as temperature measurements through release-recapture experiments (some of these results are included in Richard Wagner's PhD dissertation).

• DAMOP Poster
• What does a single atom look like?

• Electromagnetically Induced Transparency (undergraduate thesis)

For my undergraduate thesis at Reed College I designed and constructed an optical system to measure and analyze Electromagnetically Induced Transparency in thermal rubidium vapor.

• Undergraduate Thesis (pdf)

• Linear Quadrupole Trap (undergraduate research)

In summer of 2011 I worked in the Engels lab and designed and constructed a linear quadrupole trap for trapping charged particles. I also compared the observed trapping dynamics to simulations.

• Trap design and photos
• Simulations

• Quantum Dot Blinking Statistics (undergraduate research)

In summer of 2010 I participated in an NSF Research Experience for Undergraduates program at University of Arkansas. My project involved measuring high time-resolution blinking statistics of colloidal CdSe quantum dots. I developed a LabVIEW control system for driving a nanometer precision scan of quantum dot samples, so that a single quantum emitter could be identified through $g^{(2)}$ measurements. Additionally, a full-field camera system allowed for the collection of low-time resolution blinking statistics of many quantum dots simultaneously. For this system I developed a tool in C to automatically extract blinking statistics from images many quantum dots.