NESSi Documentation

Overview

This is the documentation for NESSi. Here you will find an introduction, usage examples, and the full API reference generated automatically from the source code using Doxygen + Breathe.

NESSi

• Welcome to the Non-Equilibrium Systems Simulation (NESSi) library!
  • What is NESSi?
  • How to cite
  • Structure of the software
  • Core functionalities
    • Summary of main routines
    • New routines in version 2.0.0
  • Perspective: dynamical mean-field theory
  • Developers and contributors
  • License
• Getting Started with NESSi
  • Getting the Code
  • Installation
  • Supported Platforms
    • macOS with MacPorts
    • macOS with Homebrew
    • Linux
  • Creating a Custom Program
  • Test Suite and Documentation
  • Links
• Physics Background
  • Non-equilibrium quantum many-particle physics
  • Keldysh Formalism and Nonequilibrium Green’s Functions
    • Non-equilibrium Green’s functions (NEGF)
    • Kadanoff–Baym (KB) equations
  • Mathematical formulation
    • The Keldysh contour
    • Contour-ordered Green’s functions
    • Important Keldysh components
  • Numerical solution and accuracy
  • Previous use of NESSi
    • Thermalization of a pump-excited Mott insulator
    • Doublon relaxation in photo-excited 1T-TaS₂
    • Benchmarking quantum simulators
• NESSi / libcntr Manual
  • Manual Sections
    • Preliminaries
    • Green Functions
    • Timeslices
    • Map
    • Summary: Member Functions of herm_matrix and herm_matrix_timestep[_view]
    • Contour Functions
    • Simple Algebra
    • Free Green’s Functions
    • Diagram Utilities
    • Convolution
    • Dyson Equation
    • VIE2
    • Utilities
    • Creating and Passing Input Files
    • MPI Parallelization
    • HDF5 Usage
    • Python Tools
• Manual for truncated Kadanoff-Baym equations
  • Formalism: Memory truncated time propagation
  • Truncated Green’s function
    • Overview
    • Constructors
    • Accessing individual elements
    • Density matrix
    • Forward move of the truncated time window
    • Initialization from cntr::herm_matrix
    • Text file I/O
    • HDF5 file I/O
  • Truncated Timeslices
    • Overview
    • Constructors
    • Accessing individual matrix elements
  • Truncated Map
    • Overview
    • Constructors
    • Accessing and manipulation
  • Truncated Contour Functions
    • Overview
    • Constructors
    • Accessing individual matrix elements
    • Manipulating the truncated time window
  • Timestep-wise data manipulation and access
    • Copying data between timeslices
    • Scalar multiplication and incrementation
    • Multiplication with one-time contour functions
    • Comparing Green’s functions
    • Timestep extrapolation
  • Truncated diagram utilities
  • Truncated Dyson Equation
  • Truncated VIE2
  • MPI parallelization
    • Distributed timestep array
  • HDF5 usage
    • Overview
    • Reading/writing to HDF5 files
  • Python tools
    • Creation of an input file
    • Reading Green’s functions from HDF5
• Manual for steady-state Kadanoff-Baym equations
  • Steady state Keldysh formalism
  • Overview
    • ness2
    • ness
  • Green’s functions
    • ness2::fft_array
    • ness2::herm_matrix_ness
    • ness::GF
    • ness::fft_solver
    • ness::GF_pair
  • Equilibrium Green’s functions
    • Constructing a Green’s function from a given DOS
    • Setting a Green’s function to thermal equilibrium
  • Diagram utilities
    • Bubble diagrams
  • Dyson equation
  • Parallelization with OMP
  • Utilities
    • Comparing Green’s functions
    • Data exchange with two-time functions
    • Resampling
    • HDF5 python utilities
• Example Programs
  • Installation
  • Example Pages
    • Test of accuracy of Dyson solver: equilibrium
    • Test of accuracy of Dyson solver: nonequilibrium
    • Hubbard chain
    • Holstein impurity model coupled to a bath
    • DMFT for the Holstein model
    • Lattice GW
    • DMFT with a memory-truncated time propagation
    • Steady-State Examples
• C++ API Reference
  • libcntr — Green’s function classes
    • cntr::herm_matrix
    • cntr::herm_matrix_timestep
    • cntr::herm_matrix_timestep_view
    • cntr::herm_matrix_moving
    • cntr::herm_matrix_timestep_moving
    • cntr::herm_matrix_timestep_moving_view
    • cntr::herm_pseudo
    • cntr::function
    • cntr::function_moving
  • libcntr — Utility classes
    • cntr::cyclic_timestep
  • libcntr — MPI / distributed classes
    • cntr::distributed_array
    • cntr::distributed_timestep_array
    • cntr::distributed_timestep_array_moving
  • Steady-state routines (namespace ness2)
    • ness2::herm_matrix_ness
    • ness2::grid_info
    • ness2::fft_array
    • ness2::FFT_OMP_Manager
    • ness2::bethedos
    • ness2::gauss
    • ness2::ohmic_sym
  • Steady-state routines — legacy (namespace ness)
    • ness::GF
    • ness::gauss
    • ness::ohmic_sym