SU(1,1)thermal group of bosonic strings andD-branes

Abstract

All possible Bogoliubov operators that generate the thermal transformations in thermo field dynamics form an 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 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 SU(1,1) transformation in a constant Kalb-Ramond field and compute its entropy.

Closed string thermal torus from thermo field dynamics

“…The idea of using the Fock space formulation in string theory came up in Refs. [23,24,25,26,27,28], where the thermal space was used to construct bosonic thermal boundary states interpreted as D-branes at finite temperature. To further explore the algebraic characteristics of the TFD, and to upgrade it to a powerful tool to understand string theory at finite temperature, it is first necessary to set up the connections between the TFD and the Imaginary Time formalisms, when both are applied to strings at thermal equilibrium.…”

General Unitary TFD Formulation for Superstrings

“…General Unitary TFD Formulation for Superstrings A. L. Gadelha where H, the original hamiltonian, is defined at (4), λ is a lagrange multiplier and P is given at (6). The dependence of the thermal vacuum on the lagrange multiplier comes from the Bogoliubov transformation parameters.…”

“…[6]. In a recent paper [7] the general unitary SU 1 1 T FD formulation was proposed for bosonic systems.…”

ThermalD-brane boundary states from Green-Schwarz superstrings

“…In previous works [1,2,3], we proposed a new method for obtaining thermal boundary states from bosonic D-brane states (see for reviews and related problems [4,5,6].) The main idea presented there is to thermalize the bosonic closed string by applying the Thermo Field Dynamics formalism (TFD) [7].…”