Shumway Research Group

Department of Physics • Arizona State University • Tempe • AZ
Research in Path Integral Simulations, Quantum Monte Carlo, and Semiconductor Nanostructures

Overview

[ People • Publications • Opportunties • Funding ]

People in our group

Our group currently consists of graduate and undergraduate students who work on a variety of theoretical projects. We also collaborate with other ASU professors and students in experimental nanoscience, as well as groups external to ASU. Many former group members are pursuing advanced degrees at leading universities and others are working in industry.

Research

[ Path Integrals • Quantum Dots • Nanoelectronics • Publications ]

Path Integral Methods

Path integrals allow us to solve physics problems in nanoelectronics and quantum chemistry by summing over many over trajectories. This approach is well-suited for problems involving quantum and thermal fluctuations, and it has a smooth crossover to classical physics. The path integrals may be efficiently evaluated with Monte Carlo sampling on modern PC's and high-performance computing clusters.

News: We now have our PIMC application live on NanoHUB with documentation on ASUWiki.

Quantum Dots

The term “quantum dot” can refer to any structure that exhibits three-dimensional quantum confinement of electrons. We focus our studies on self-assembled heteroepitaxial dots, especially InGaAs/GaAs and Ge/Si. With NSF-CAREER funding we have developed efficient path integral simulations for quantum dots that allow us to calculate equilibrium dot occupation, exciton recombination rates, polarizabilities, and other properties of realistic quantum dot models.

Nanoelectronics

At the nanometer length scale, electronic currents exhibit quantum effects such as quantized conductance and ballistic transport. Through the SRC-NRI SouthWest Institute for Nanoelectronics (SWAN) we are developing new path-intergral simulation techniques to evaluate novel nanoscale switching devices. Our theoretical approach utilizes current-current fluctuations in the framework of Kubo's linear response theory.

Resources

[ Simulation Tools • Tutorials • Courses • Lists of Web Resources]

Simulation Tools

As part of our the broader impact of our NSF-CAREER research grant, we develop and distribute open-source simulation tools for modeling quantum dots. These tools are object-oriented and make heavy use of structure XML and HDF5 data formats. We regularly run these simulations on Mac OSX and Linux PC's and high-performance computing centers (ASU's Fulton HPC and UT-Austin's TACC).

Classroom Tutorials

As further outreach, we have ported key parts of our object-oriented path integral simulation code to Java. This classroom demo performs live simulations of sixteen bosons to demonstrate Feynman's path integral model of Bose condensation. At ASU we have used this tutorial to supplement lectures on path integrals in our senior level quantum mechanics and graduate statistical mechanics courses.