Welcome to SpM’s documentation!

This is a documentation of Sparse Modeling (SpM) tool for analytical continuation.

What is SpM ?

A sparse-modeling tool for computing the spectral function from the imaginary-time Green function. It removes statistical errors in quantum Monte Carlo data, and performs a stable analytical continuation. The obtained spectral function fulfills the non-negativity and the sum rule. The computation is fast and free from tuning parameters.

License

This package is distributed under GNU General Public License version 3 (GPL v3).

When you publish a publication that includes results obtained using this package, we kindly ask you to cite the following articles

• SpM method

  J. Otsuki, M. Ohzeki, H. Shinaoka, K. Yoshimi, “Sparse modeling approach to analytical continuation of imaginary-time quantum Monte Carlo data” Phys. Rev. E 95, 061302(R) (2017).

• SpM package

  K. Yoshimi, J. Otsuki, Y. Motoyama, M. Ohzeki, and H. Shinaoka, “SpM: Sparse modeling tool for analytic continuation of imaginary-time Green’s function” Comput. Phys. Commun. 244, 319-323 (2019).

• SpM-Pade method (if you use)

  Y. Motoyama, K. Yoshimi, and J. Otsuki, “Robust analytic continuation combining the advantages of the sparse modeling approach and Pade approximation”, [arXiv:2109.08370](https://arxiv.org/abs/2109.08370).

Contents

• 1. How to install
  • 1.1. Requirement
  • 1.2. Download
  • 1.3. Build
  • 1.4. Test
• 2. Tutorials
  • 2.1. Fermionic system
  • 2.2. Bosonic system
  • 2.3. SpM-Pade method
• 3. Algorithm
• 4. Calculation flow
  • 4.1. Overview of calculation flow
  • 4.2. Sparse modeling procedure
• 5. Input files
• 6. Output files
  • 6.1. List of files
  • 6.2. Details of each files