Anti-brane singularities as red herrings

Abstract

Unphysical 3-form flux singularities near anti-branes have been argued to get resolved in the classical supergravity regime when brane polarisation is properly taken into account. The only example that does not seem to fit this logic is the D6-brane because of a no-go theorem for well behaved supergravity solutions with negative D6 charge. In this paper we first review the existing results demonstrating how brane polarisation resolves singularities for D3-branes and then we improve on the description of the polarisation of D6-branes into KK5 dipoles. We argue that the meta-stable state carries exactly zero (anti-)D6 charge, which is the unique way around the no-go theorem. We then provide numerical evidence for well-behaved solutions that describe such meta-stable states. arXiv:1907.05295v1 [hep-th]

Classical de Sitter solutions in three dimensions without tachyons?

“…We argued that the conditions for open string stability would be of the form (3.50). We have explicitly verified that the stability of the anti-D6 was satisfied in case we can trust existing probe results [68] but that the stability of the anti-D2 is a worry due to Eq. (4.8), although no concrete brane-flux decay computation is carried out in lack of a concrete model without closed string tachyons after flux quantization.…”

“…Note that anti-D6 branes, wrapping 4d cycles will probably extend in the whole bulk. But it seems that the arguments of [68] leading to (4.4) are model independent, although the actual bound might be tighter than (4.4) due to backreaction. We have shown that in our model we could obey the bound (4.4), but not parametrically.…”

“…Not only due to possible strong coupling effects but also the classical backreaction of the anti-branes (see [69] for some pioneering work) could be a worry and potentially enhance the instabilities [70]. However non-trivial evidence in favor of the probe action results came from the complementary blackfold treatments carried out in [71][72][73] as well as from arguments pointing to the absence of dangerous singularities due to backreaction [68,[74][75][76]. It is however quite likely that the actual bounds are a bit more strict than the probe results.…”

No-scale and scale-separated flux vacua from IIA on G2 orientifolds

“…Anti-D2-branes are then the natural SUSY-breaking uplift ingredient for which a probe computation à la [54] would suggest the solutions can be metastable. However this probe computation has been refuted in [55], but that criticism in turn was argued to be essentially harmless because of the arguments in [56][57][58][59], although other problems associated to anti-brane uplifting could persist as reviewed in [6].…”

An update on moduli stabilization with antibrane uplift

“…Finally, an anti-D3 brane is introduced which breaks supersymmetry. 2 The second and third step were debated over the years [9][10][11][12][13][14][15][16][17][18][19][20][21] and whereas there is not yet a consensus over the last step, there are recent positive results indicating the validity of the second step [22][23][24][25][26][27][28][29].…”