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Manuscript Title: SNEG - Mathematica package for symbolic calculations with second-quantization-operator expressions
Authors: Rok Zitko
Program title: SNEG
Catalogue identifier: AEJL_v1_0
Distribution format: tar.gz
Journal reference: Comput. Phys. Commun. 182(2011)2259
Programming language: Mathematica.
Computer: Any computer which runs Mathematica.
Operating system: Any OS which runs Mathematica.
RAM: Problem dependent
Keywords: Second quantization, Non-commuting operators, Commutators, Wick's theorem, Dirac bra-ket notation.
PACS: 31.15.-p, 07.05.Bx, 03.70.+k, 01.50.H-.
Classification: 2.9, 5, 6.2.

Nature of problem:
Manipulation of expressions involving second quantization operators and other non-commuting objects. Calculation of commutators, anticommutators, expectation values. Generation of matrix representations of the Hamiltonians expressed in the second quantization language.

Solution method:
Automatic reordering of operator strings in some well specified canonical order; (anti)commutation rules are used where needed. States may be represented in occupation-number representation. Dirac bra-ket notation may be intermixed with non-commuting operator expressions.

For very long operator strings, the brute-force automatic reordering becomes slow, but it can be turned off. In such cases, the expectation values may still be evaluated using Wick's theorem.

Unusual features:
SNEG provides the natural notation of second-quantization operators (dagger for creation operators, etc.) when used interactively using the Mathematica notebook interface.

Running time:
Problem dependent