This dataset contains partial spectral functions (PSFs) used in the related preprint "Computing and compressing local vertex functions in imaginary and real frequencies from the multipoint numerical renormalization group using quantics tensor cross interpolation".
The PSFs were computed with the multipoint numerical renormalization group. The underlying model is the single impurity Anderson model (SIAM).
The code related to the preprint, which computes imaginary- and real-frequency four-point vertices in tensor train format from these PSFs, can be found on [GitHub](https://github.com/MFrankenbach/TCI4Keldysh.git).
See also there for a reference to the preprint. 

There are a total of seven sets of PSFs, each computed for a different set of physical parameters. The hybridization strength
Δ can be computed via Δ=U/(πu). By β, we denote the inverse temperature.
- SIAM\_u=0.50: U=0.05, u=0.5, β=2000
- SIAM\_u=1.00: U=0.05, u=1.0, β=2000
- SIAM\_u=1.50: U=0.05, u=1.5, β=2000
- siam05\_U0.05\_T0.05\_Delta0.0318: U=0.05, u=0.5004, β=20
- siam05\_U0.05\_T0.005\_Delta0.0318: U=0.05, u=0.5004, β=200
- SIAM\_u3\_U0.05\_T0.0005\_Delta0.0053052: U=0.05, u=3.0, β=2000
- SIAM\_u5\_U0.05\_T0.0005\_Delta0.0031831: U=0.05, u=5.0, β=2000

Parameters of the computations can be read from the respective `mpNRG_*.mat` files. The trailing labels ph,pht,pp refer to the different frequency channels, but in this case, none of the parameters have been varied with the channel.
*NOTE*: The value of the field "Delta" in the `.mat` files does not always correspond to the actual Δ; more precisely, the field "Delta" is sometimes Δ/π. The true Δ can be reliably read either from the field "Rhoin" (search for the maximum of the array) or from ˝RhoV2in" (this is a scalar).