String field theory solution for any open string background

Abstract

We present an exact solution of open bosonic string field theory which can be used to describe any time-independent open string background. The solution generalizes an earlier construction of Kiermaier, Okawa, and Soler, and assumes the existence of boundary condition changing operators with nonsingular OPEs and vanishing conformal dimension. Our main observation is that boundary condition changing operators of this kind can describe nearly any open string background provided the background shift is accompanied by a timelike Wilson line of sufficient strength. As an application we analyze the tachyon lump describing the formation of a D(p−1)-brane in the string field theory of a Dp-brane, for generic compactification radius. This not only provides a proof of Sen's second conjecture, but also gives explicit examples of higher energy solutions, confirming analytically that string field theory can "reverse" the direction of the worldsheet RG flow. We also find multiple D-brane solutions, demonstrating that string field theory can add Chan-Paton factors and change the rank of the gauge group. Finally, we show how the solution provides a remarkably simple and nonperturbative proof of the background independence of open bosonic string field theory.

Ramond-Ramond couplings of D-branes

“…Our observation is in a good contrast with a recent report [59] on multiple D-brane solutions in cubic open string field theory [60]. Since no good relation (field redefinition) between the BSFT and the cubic open string field theory, it is plausible that the theory configuration space allowed for each theory is different from the first place.…”

Supersymmetry in open superstring field theory

“…Describing broken supersymmetries is closely related to the issue of background independence in string field theory, and should be important for understanding the appearance of D-brane charges in the supersymmetry algebra. Further progress in this direction may be possible following [8][9][10].…”

“…All three symplectic forms are graded antisymmetric, 10) and nondegenerate on their respective domains [1]. Moreover, the BRST operator satisfies…”

“…The third term vanishes assuming the equations of motion 10) and therefore represents a symmetry which vanishes on-shell. Therefore our main task is to compute T. For the above interpretation of the supersymmetry algebra to be consistent, we must require the following properties:…”

Comments on lump solutions in SFT

“…analytic solutions interpretable as lower dimensional branes (meant to complete the analytic proof of the three conjectures by Sen [14]), is instead poorer. There have been essentially two attempts to find such analytic solutions: the first is the so-called BMT proposal [15][16][17], the second is the most recent one formulated in [18], which we will refer to as EM. They are both modeled on the Erler-Schnabl (ES) solution [5], an alternative simpler formulation of the original tachyon vacuum (TV) solution (for recent reviews on the whole subject, see [19][20][21][22]).…”