NEW DIRECTIONS IN QUANTUM TRANSPORT ALGORITHMS
Abstract
Title: New directions in quantum transport algorithms Objective: The goal of this project is to research and develop novel algorithms for quantum transport systems and serve the nanoelectronics and condensed matter physics communities through improvement in the open source quantum transport package Kwant. Approach: The team of four scientists will collaborate to develop novel efficient quantum transport algorithms. By combining a mathematical, algorithmic and computational approach, the team will develop new methods that, • numerically calculate the electrostatics of nanostructures in a scalable fashion • numerically calculate the influence of nearby conducting (and superconducting) structures beyond the usual quasi one dimensional approximation. i.e. provide a numerical solution to the multidimensional scattering problem. The new methods will be made available to the broader research community through improved versions of the freely available, open-source quantum transport package Kwant, originally developed by the same team. Statement of Work: Specific Research Tasks are: 1. Subsequent relaxation of approximations for electrostatics: The interaction of a nanoscale system (governed by quantum mechanics) with its electrostatic environment is in general complex. Depending on the parameter regime, the problem can however sometimes be simplified using approximate techniques. The team will use a coarse-grained description when appropriate to improve efficiency, while maintaining the full quantum simulation capabilities in the software. 2. Multidimensional scattering problem: A scattering problem always involves a scatterer embedded in a bulk environment. To solve it, it is necessary to obtain appropriate boundary conditions for the scatterer, for example in the form of a self-energy. For quasi-1D scattering this involves solving a one-dimensional integral, that can be recast into the form of an eigenproblem with discrete eigenvalues. For a higher-dimensional scattering problem (a scatterer embedded in two or three dimensions), a multi-dimensional integral needs to be computed. When recast into the form of an eigenproblem, the eigenvalues however now form continuous manifolds – this does not lend itself to a straightforward numerical solution. The team will hence tackle the problem using different approaches that include Green’s functions techniques, wave function matching in momentum space or eigenvalue formulation of the wave function matching problem. ONR Relevance: High quality open-source quantum transport modeling tools are absolutely essential for making progress in today’s forefront research in nanoelectronics. Quantum transport modeling has been a key thrust of ONR’s nanoelectronics program for at least two decades. Traditionally the research community relied upon a small cadre of specialists who are either trained in one of the few commercially available modeling tools or developed in-house software that are proprietary and suffers from poor portability, documentation and support. Kwant is among the first freely available quantum transport modeling tools that designed specifically to benefit the majority of the research community who are non-specialists.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 08, 2016
- Source ID
- N000141512732
Entities
People
- Christoph Groth
Organizations
- Alternative Energies and Atomic Energy Commission
- Office of Naval Research
- United States Navy