Non-perturbative vacuum destabilization and D-brane dynamics

Abstract

Abstract:We analyze the process of string vacuum destabilization due to instanton induced superpotential couplings which depend linearly on charged fields. These nonperturbative instabilities result in potentials for the D-brane moduli and lead to processes of D-brane recombination, motion and partial moduli stabilization at the non-perturbative vacuum. By using techniques of D-brane instanton calculus, we explicitly compute this scalar potential in toroidal orbifold compactifications with magnetized D-branes by summing over the possible discrete instanton configurations. We illustrate explicitly the resulting dynamics in globally consistent models. These instabilities can have phenomenological applications to breaking hidden sector gauge groups, open string moduli stabilization and supersymmetry breaking. Our results suggest that breaking supersymmetry by Polonyi-like models in string theory is more difficult than expected.

Kähler metrics and gauge kinetic functions for intersecting D6‐branes on toroidal orbifolds – The complete perturbative story

“…k=1 U (4) c k , and the matter spectrum matches the one in [1] with corrections in [67] taken into account. For the D6 c j -branes, the orientifold image D-branes listed here have a different shape ( τ Z 2 c j ) = ( τ Z 2 c j ) + (1, 0, 1) because we performed a simultaneous sign-flip of the toroidal wrapping numbers on T 2…”

“…The displacement ( σ ai,i∈{3,4} ) = (1, 0, 0) modifies also the a i b j and a i c j sectors for i ∈ {3, 4} in table 26 and the corresponding entries in the anomaly-matrix (101) as follows: the a i b j sectors contribute (1, 1, 2, 1; 4, 1; 1, 1) + (1, 1, 2, 1; 1, 4; 1, 1) + (1, 1, 1, 2; 1, 4; 1, 1) + (1, 1, 1, 2; 4, 1; 1, 1) and the a i c j sectors (1, 1, 2, 1; 1, 1; 4, 1) + (1, 1, 2, 1; 1, 1; 1, 4) + (1, 1, 1, 2; 1, 1; 1, 4) + (1, 1, 1, 2; 1, 1; 4, 1) to the massless spectrum, and the associated anomaly matrix   . However, as communicated to me by some authors of [1], the spectrum in table 10 of [1]v3 belongs to a D-brane configuration without any discrete displacement and Wilson line parameters turned on, and the missing states in the a i a j sector with i ∈ {1, 2} and j ∈ {3, 4} can be found in table 2 of [67].…”

“…This does not constrain the displacements σ 1 a i along the first two-torus T 2 (1) , but the fixed point sets F a i 1 and thus the displacements (σ 2 a i , σ 3 a i ) have to be pairwise identical among two different a i -branes with opposite Z (1) 2 eigenvalue in order to achieve cancellation of the exceptional RR tadpole at each Z (1) 2 fixed point. Setting ( σ a i ) = ( 0) for all a i branes leads to a matching of all a i a j and a i a j sectors with [1] when including the corrections to the latter in table 2 of [67].…”

“…The complete massless matter spectrum on intersecting rigid D6-branes on T 6 /Z 2 × Z 2 with discrete torsion which is T-dual to the magnetised D9/D5-brane example 3 in[1] including the corrections in[67]. The spectra match up to reordering and complex conjugation of all a 3 and a 4 states and upon the recombination of the D6 b j and D6 c j -branes with their orientifold images to the reduced gauge group 2 j=1 Sp(4) b j × 2 k=1 Sp(4) c k as discussed in the text.Example 3 on T 6 /Z 2 × Z 2 : Kähler metrics and gauge kinetic functions involving brane a 1…”

Warping the Weak Gravity Conjecture

“…See[61] for an explicit computation of the instanton generated scalar potential for open string moduli in toroidal orbifold compactifications with magnetized D-branes. 14 This is similar -but slightly different -to the loophole discussed in[14] to achieve Natural Inflation consistently with the strong form of the Generalized Weak Gravity Conjecture.…”