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"NRG Ljubljana" is a general-purpose flexible framework for performing large scale numerical renormalization group (NRG) calculations for
quantum impurity problems. It is highly extensible
without sacrificing numerical efficiency.
I advocate open access to knowledge in science.
The "NRG Ljubljana" framework is thus licenced under the General public licence (GPL).
You are entitled to run the program, for any desired purpose, study
how the program works and modify it, redistribute copies and improve
the program. I would, however, appreciate citations to Phys. Rev. B 79,
085106 (2009) and if you make use of the results produced with this code.
The PRB paper introduced a new discretization scheme for NRG that led way
to much improved results at high frequencies and high temperatures, while
the Zenodo DOI is assigned to a recent (2021) version of the "NRG Ljubljana" code.
Download the current
version of "NRG Ljubljana" from github (external link, zip file)
"NRG Ljubljana" - open source numerical renormalization group code
The package should work unmodified on any modern Unix (MacOS is fine) or
Linux distribution with a good standards-compliant C++ compiler (C++17
required, mostly tested with GCC 9.3.0). It requires BLAS/LAPACK libraries,
Boost, GNU Scientific Library (GSL), GNU Multiple Precision library (GMP),
HDF5 (optionally) and Wolfram Mathematica. Mathematica is only required for
the initialization of the problem (basis construction, diagonalisation of
the initial Hamiltonian, transformations of the operator matrices, etc.); if
Mathematica is not present, the code will still work with manually generated
Legacy versions are documented here.
Examples and documentation
Library of examples (2019)
NRG UFU/2019 Advanced Studies School,
in Feb 2019 in Uberlândia, Brazil.
A Mathematica implementation of the NRG method is also available.
It illustrates the main ideas of the algorithm on the single-impurity
Anderson model using simple Mathematica notebook interface. It
calculates the thermodynamic quantities and the expectation values of
arbitrary local operators.
Last modified: 14. 9. 2023
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