Comments on Takahashi-Tanimoto's scalar solution

We study the identity-based solution of Witten's cubic bosonic open string field theory constructed by Takahashi and Tanimoto, which is claimed to describe the tachyon vacuum. We argue that the observables of the solution coincide with those of the tachyon vacuum using the method proposed by Kishimoto and Takahashi. We also discuss how to treat the kinetic term of the string field theory expanded around it.Comment: 25 pages, 4 figures, v3: several clarifications added, corrected statements about operator U, v4: comments on operator U_k are adde

Multiloop Amplitudes of Light-cone Gauge Superstring Field Theory: Odd Spin Structure Contributions

We study the odd spin structure contributions to the multiloop amplitudes of light-cone gauge superstring field theory. We show that they coincide with the amplitudes in the conformal gauge with two of the vertex operators chosen to be in the pictures different from the standard choice, namely (-1,-1) picture in the type II case and -1 picture in the heterotic case. We also show that the contact term divergences can be regularized in the same way as in the amplitudes for the even structures and we get the amplitudes which coincide with those obtained from the first-quantized approach.Comment: 32 pages, 2 figure

Light-cone Gauge String Field Theory and Dimensional Regularization

We review our recent proposals to dimensionally regularize the light-cone gauge string field theory.Comment: 10 pages, 5 figures, A contribution to the proceedings of "SFT2010", held at YITP, Kyoto, Japan, October 18-22, 201