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Manuscript Title: Hilbert space and structure constants of descendant fields in two- dimensional conformal theories.
Authors: M. Lassig, G. Mussardo
Program title: STRIP
Catalogue identifier: ABZT_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 66(1991)71
Programming language: Mathematica.
Computer: DECstation 3100.
Operating system: ULTRIX.
Keywords: Conformal field theory, Two-dimensional systems away from criticality, Spectrum of the Transfer matrix.
Classification: 7.7.

Nature of problem:
To compute the spectrum of the transfer matrix for massive (1+1) dimensional quantum field theories.

Solution method:
The massive regime is seen as a deformation of the model at its massless critical point, where it can be solved exactly with the methods of conformal field theory. This program encodes an efficient algorithm for the computation of the necessary data at the conformal point, namely (a) a convenient basis of the Hilbert space, truncated to a finite number of elements, and (b) the "interaction" matrix elements, i.e. the structure constants of the perturbing operator between these states.

Running time:
Strongly dependent on the dimension of the truncated Hilbert space; about 1 sec CPU to compute each interaction matrix element, and about 1 min CPU to diagonalize a 200 X 200 Hamiltonian matrix.