SeQuant
SeQuant is a Mathematica code that can help to manipulate automatically second-quantized expressions in quantum mechanics. The most common manipulations are the application of Wick's theorem and subsequent reindexing and expressions simplification. The code is very general: arbitrary number of spaces, arbitrary particle types, arbitrary operator rank and permutational symmetry can be handled. The generality has a price -- the code is probably too slow to derive CCSDT expressions.
SeQuant is a work in progress, so you should not expect it to be bug-free. It can be used as a teaching tool, e.g. for deriving CCSD equations. It has been helpful in research also, i.e. in deriving expressions for MP2-R12 and CC-R12 methods and a study of the nonadiabatic ansatze with Arteum Bochevarov and David Sherrill. Feel free to download and try it our for yourself.
Authors
License and Warranty
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
Refer to the full text of the GNU General Public License. You can obtain the most up-to-date version of GPL if you write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
Prerequisites
- Mathematica (version 4 or higher) from Wolfram Research Inc..
Download
- SeQuant.nb (updated November 26, 2007).
Examples
- CCSD.nb -- shows how to derive CCSD equations
- cisdetn.nb -- shows how to derive matrix elements for the nonadiabatic CISDeTn method (see Bochevarov, Valeev, Sherrill, Mol. Phys. (2004).
To run any of these examples in Mathematica, you must first open sequant.nb and execute its first input cell.