标题： T对偶坐标依赖性使有效的Kalb-Ramond场变得非平凡 显示英文标题

标题： T-dual-coordinate dependence makes the effective Kalb-Ramond field nontrivial

摘要： 我们证明了弦理论是未定向的这一事实并不必然使Kalb-Ramond场消失。 我们研究了在弱曲背景中传播的开弦理论。 有效 Kalb-Ramond场 $B^{eff}_{\mu\nu}$，即在边界条件解上得到的有效理论的背景场，不依赖于 $\Omega$-偶有效坐标 $q$，而是依赖于其T对偶的 $\tilde{q}$，该T对偶是 $\Omega$-奇的。 这破坏了标准证明，即带有 $B_{\mu\nu}^{eff}$的项应该消失。 从世界面运动方程中，我们将 $B_{\mu\nu}^{eff}$与扭转势联系起来。 显示英文摘要

摘要： We show that the fact that the string theory is unoriented does not necessarily force the Kalb-Ramond field to vanish. We investigated the theory of the open string propagating in the weakly curved background. The effective Kalb-Ramond field $B^{eff}_{\mu\nu}$, the background field of the effective theory obtained on the solution of the boundary conditions, does not depend on the $\Omega$-even effective coordinate $q$, but on its T-dual $\tilde{q}$ which is $\Omega$-odd. This brakes the standard proof that the term with $B_{\mu\nu}^{eff}$ should vanish. From the world-sheet equations of motion we identify $B_{\mu\nu}^{eff}$ with the torsion potential.