arXiv:hep-th/0203222 · Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields
SU(1,1) thermal group of bosonic strings andD-branes
M. C. B. Abdalla, A. L. Gadelha, Ion V. Vancea
Abstract
All possible Bogoliubov operators that generate the thermal transformations in thermo field dynamics form an $\mathrm{SU}(1,1)$ group. We discuss this construction in the bosonic string theory. In particular, the transformation of the Fock space and string operators generated by the most general $\mathrm{SU}(1,1)$ unitary Bogoliubov transformation and the entropy of the corresponding thermal string are computed. Also, we construct the thermal D-brane generated by the $\mathrm{SU}(1,1)$ transformation in a constant Kalb-Ramond field and compute its entropy.