irbasis: Open-source database and software for intermediate-representation basis functions of imaginary-time Green's function
This is an incremental tool for researchers in computational physics to simplify quantum simulations.
The authors tackled the problem of representing imaginary-time Green's functions in quantum models by providing an open-source library with pre-computed basis functions, enabling compact and efficient calculations.
The open-source library, irbasis, provides easy-to-use tools for two sets of orthogonal functions named intermediate representation (IR). The IR basis enables a compact representation of the Matsubara Green's function and efficient calculations of quantum models. The IR basis functions are defined as the solution of an integral equation whose analytical solution is not available for this moment. The library consists of a database of pre-computed high-precision numerical solutions and computational code for evaluating the functions from the database. This paper describes technical details and demonstrates how to use the library.