Quantum field theories in finite volume: Excited state energies
Abstract
We develop a method of computing the excited state energies in Integrable Quantum Field Theories (IQFT) in finite geometry, with the spatial coordinate compactified on a circle of circumference R. The IQFT "commuting transfer matrices" introduced earlier [Commun. Math. Phys. 177 (1996) 381] for Conformal Field Theories (CFT) are generalized to nonconformal IQFT obtained by perturbing CFT with the operator Φ_{1,3}. We study the models in which the fusion relations for these "transfer matrices" truncate and provide closed integral equations which generalize the equations of the thermodynamic Bethe ansatz to excited states. The explicit calculations are done for the first excited state in the "scaling LeeYang model".
 Publication:

Nuclear Physics B
 Pub Date:
 February 1997
 DOI:
 10.1016/S05503213(97)000229
 arXiv:
 arXiv:hepth/9607099
 Bibcode:
 1997NuPhB.489..487B
 Keywords:

 High Energy Physics  Theory;
 Condensed Matter;
 Mathematics  Quantum Algebra;
 Nonlinear Sciences  Exactly Solvable and Integrable Systems
 EPrint:
 54 pages, harvmac, epsf, TeX file and postscript figures packed in a single selfextracting uufile. Compiles only in the `Big' mode with harvmac