String theory gives S matrix elements om which is not possible to read any gauge information. Using factorization we go off shell in the simplest and most naive way and we read which are the vertices suggested by string. To compare with the associated Effective Field Theory it is natural to use color ordered vertices. The alpha'=0 color ordered vertices suggested by string theory are more efficient than the usual ones since the three gluon color ordered vertex has three terms instead of six and the four gluon one has one term instead of three. They are written in the so called Gervais-Neveu gauge. The full Effective Field Theory is in a generalization of the Gervais-Neveu gauge with alpha') corrections. Moreover a field redefinition is required to be mapped to the field used by string theory. We also give an intuitive way of understanding why string choose this gauge in terms of the minimal number of couplings necessary to reproduce the non abelian amplitudes starting from color ordered ones.
We study the worldsheet theory of bosonic string from the point of view of the BV formalism. We explicitly describe the derived Poisson structure which arizes when we expand the Master Action near a Lagrangian submanifold. The BV formalism allows us to clarify the mechanism of holomorphic factorization of string amplitudes.
The potential of the closed bosonic bulk tachyon is investigated using $\mathcal{N}~=~1$ closed superstring field theory formulated around Berkovits' and Vafas embedding of the bosonic string into the superstring. From this point of view the bosonic minimum gets destabilized by new deformations of the underlying CFT. Another critical point of the potential is identified by solving the equation of motions and the properties of this new solution are discussed.
Excited D-brane decay in Cubic String Field Theory and in Bosonic String Theory
在立方弦场论中，利用对应于壳层闭弦顶点算符的规范不变算符，我们计算了两个开弦快子或规范场到一个闭弦快子或引力子的衰变振幅，直到能级2.然后，我们计算了玻色弦论中相同的振幅，并证明了两种理论中的振幅具有完全相同的极点结构。我们还扩展了玻色弦论中Mandeltron变量s=0附近的衰变振幅，并证明了它们的前导接触项与快子的Dirac Born Infeld作用量完全一致，该作用量包括开弦和闭弦快子。
We propose the action for the nonrelativistic string invariant under general coordinate transformations on the string worldsheet. The Hamiltonian formulation for the nonrelativistic string is given. Particular solutions of the Euler-Lagrange equations are found in the time gauge.
Through the Casimir effect, we obtain a temperature correction to the ground state mass of the Bosonic string. Accordingly, we show that higher than the temperature $\approx 1/2π$, the Tachyon attain real mass, and also we find massive Graviton for nonzero temperatures. As another consequence, we demonstrate that for temperatures higher than the Hagedorn temperature, the string would find again a Tachyonic state.
The Presentation of the Quantum Algebra of Observables of the Closed Bosonic String in 1+3 Dimensions: The Presentation in Manifestly Lorentz Covariant Form
We discuss a renormalization procedure for a classical bosonic string coupled to a massless scalar field. The classical equations of motion for this system are non-renormalizable if the number of spacetime dimensions exceeds four. Our analysis indicates that string excitation modes must be included to make the string a finite object.
