Algorithms for Lattice Fermions

• Applicant: Professor Dr. Fakher Fakhry Assaad
• Subject Area: Nuclear and Elementary Particle Physics, Quantum Mechanics, Relativity, Fields ; Software Engineering and Programming Languages ; Theoretical Condensed Matter Physics
• Term: from 2018 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 390966303

Material science is a complex multi-scale problem such that complementary methods have to be used to describe physics at different energy scales. Low energy collective and emergent phenomena such as superconductivity, topological phases of matter or magnetism, are described by models of interacting fermions on a lattice. The aim of the ALF-package is to provide a unified framework to tackle a number of fermion models within the so called auxiliary field quantum Monte Carlo approach. It provides standards so as to specify very general models, standards to define the lattice structure, and standards to compute different types of observables. Being a stochastic approach, it also comes with an error analysis library. To the best of our knowledge, ALF is a unique package in the sense that it includes many model systems. We foresee that it will impact not only in the solid state community, but also in atomic, nuclear and particle physics. The ALF is at the prototype level and is already available at http://alf.physik.uni-wuerzburg.de/. The aim of this project is to:i) Define a common platform such that the aforementioned groups of researchers can collaboratively develop the ALF.ii) Formulate a high level documentation so as to assure sustainability of the ALF.iii) Make quantum Monte Carlo methods accessible enough so that everybody is able to verify the results derived from other methods.iv) Provide an easy access to the domain of correlated-electron systems so as to play with new ideas at a minimal programming cost.

• DFG Programme: Research data and software (Scientific Library Services and Information Systems)
• Co-Investigator: Dr. Florian Goth