The TRIQS arbitrary Crossing Approximation (XCA) impurity solver

triqs_xca 0.1.0

This is the homepage of triqs_xca 0.1.0. For changes see the changelog page.

The TRIQS arbitrary Crossing Approximation (XCA) impurity solver triqs_xca can solve generic multiband Anderson impurity problems approximately by perturbative expansion in the coupling to the environment (a.k.a. the hybridization function \(\Delta(\tau)\)).

This implementation is leveraging the sum-of-exponentials (SOE) trick to achieve parametrically better computational complexity compared to direct integration and uses the Discrete Lehmann Representation (DLR) for representing response functions.

Learn how to use triqs_xca in the Documentation.

Citation

We kindly ask you to cite the following method papers when using triqs_xca in your work

[1]

J. Kaye, Z. Huang, H. U.R. Strand, D. Golež, Phys. Rev. X 14, 031034 (2024)

[2]

Z. Huang, D. Golež, H. U.R. Strand, J. Kaye, SciPost Phys. 19, 121 (2025)

[3]

J. Kaye, H. U.R. Strand, N. Wentzell, J. Open Source Softw., 9(100), 6297, (2024)

[4]

J. Kaye, K. Chen, O. Parcollet, Phys. Rev. B 105, 235115 (2021)

Note that this application uses the TRIQS library, please also see its citation page, as well as the Adapol package, see its citation page.