Functional equation for the string effective action

A functional equation for the purely gravitational part of the string effective action is found. Among its solutions are the extended Euler densities and products of Wely tensors. A possible recipe for the Ricci temrs is given.     

Field redefinition dependence of the low energy string effective action

We consider the effect of field redefinitions on the general form of the torsion dependent terms in theO(R) ³ string action.     

Dynamical approach to conformal gravity and the bosonic string effective action

We show that a theory invariant under the full local conformal group in a coset realization contains naturally the massless degrees of freedom of the closed bosonic string. This effective theory is alternative to the bosonic part of SupergravityN=1 as given by Manton and Chapline [4].     

Inverse scattering method and soliton double solution family for string effective action

A so-called modified Hauser-Ernst-type extended double-complex linear system is established and used to develop a new inverse scattering method for solving the equations of motion of the string effective action describing the coupled gravity, dilaton and Kalb-Ramond fields. The reduction procedures in this inverse scattering method are found to be fairly simple, which makes the application of the inverse scattering method fine and effective. As an application, a concrete family of soliton double solutions for the considered theory is obtained.      

The geometrical form for the string space-time action

In the present article, we derive the space-time action of the bosonic string in terms of geometrical quantities. First, we study the space-time geometry felt by a probe bosonic string moving in antisymmetric and dilaton background fields. We show that the presence of the antisymmetric field leads to space-time torsion, and the presence of the dilaton field leads to space-time non-metricity. Using these results we obtain the integration measure for space-time with stringy non-metricity, requiring its preservation under parallel transport. We derive the Lagrangian depending on stringy curvature, torsion and non-metricity.     

How to create an Alice string (half-quantum vortex) in a vector Bose-Einstein condensate

We suggest a procedure of how to prepare a vortex with N=1/2 winding number—a counterpart of the Alice string-in Bose-Einstein condensates.     

Off-shell effective actions in string theory

A new, “off-shell”, approach to conformal invariance, β-functions and field equations in first quantized string theory is presented. The method, valid to all orders in the weak-field expansion and non-perturbatively in α′, is illustrated for a tachyon background at genus zero and one level. For a particular choice, we derive a Zamolodchikov-type equation for the effective action.     

The effective action for chiral fermions

We present an exact formula for the imaginary part of the effective action for chiral fermions in complex representations of the gauge group G, in the presence of an arbitrary external gauge field configuration. This result provides a unified treatment of both local and global anomalies and a precise characterization of some of the special properties of chiral fermions.