Domain walls inside localised orientifolds

The equations of motion of toroidal orientifold compactifications with fluxes are in one-to-one correspondence with gauged supergravity if the orientifold (and D-brane) sources are smeared over the compact space. This smeared limit is identical to the approximation that ignores warping. It is therefore relevant to compare quantities obtained from the gauged supergravity with the true 10d solution with localised sources. In this paper we find the correspondence between BPS domain walls in gauged SUGRA and 10D SUGRA with localised sources. Our model is the simplest orientifold with fluxes we are aware of: an O6/D6 compactification on T^3/Z_2 in massive IIA with H_3-flux. The BPS domain walls correspond to a O6/D6/NS5/D8 bound state. Our analysis reveals that the domain wall energy computed in gauged SUGRA is unaffected by the localisation of the O6/D6 sources.Comment: 26 pages, 1 figur

Antibranes don't go black

When D-branes are inserted in flux backgrounds of opposite charge, the resulting solution has a certain singularity in the fluxes. Recently it has been argued, using numerical solutions, that for anti-D3 branes in the Klebanov-Strassler background these singularities cannot be cloaked by a horizon, which strongly suggests they are not physical. In this note we provide an analytic proof that the singularity of all codimension-three antibrane solutions (such as anti-D6 branes in massive type IIA supergravity or anti-D3 branes smeared on the T^3 of R^3xT^3 with fluxes) cannot be hidden behind a horizon, and that the charge of black branes with smooth event horizons must have the same sign as the charge of the flux background. Our result indicates that infinitesimally blackening the antibranes immediately triggers brane-flux annihilation, and strengthens the intuition that antibranes placed in flux with positive charge immediately annihilate against it.Comment: 9 pages, 1 figur

Localised anti-branes in non-compact throats at zero and finite T

We investigate the 3-form singularities that are typical to anti-brane solutions in supergravity and check whether they can be cloaked by a finite temperature horizon. For anti-D3-branes in the Klebanov-Strassler background, this was already shown numerically to be impossible when the branes are partially smeared. In this paper, we present analytic arguments that also localised branes remain with singular 3-form fluxes at both zero and finite temperature. These results may have important, possibly fatal, consequences for constructions of meta-stable de Sitter vacua through uplifting.Comment: 18 + 9 page

Investigating the Effects of a Persuasive Digital Game on Immersion, Identification, and Willingness to Help

Recent years have seen a tremendous rise in the development and distribution of persuasive games: digital games that are used to influence players’ attitudes and/or behavior. Three studies (NStudy 1 = 134; NStudy 2 = 94; NStudy 3 = 161) tested the effects of a persuasive game on immersion, identification, and willingness to help. The results showed that playing the persuasive game did not result in substantially stronger willingness to help, relative to the control conditions. Video and printed text resulted in more immersion than the digital game, but playing the game resulted in substantially higher perceptions of embodied presence

Dynamics of Generalized Assisted Inflation

We study the dynamics of multiple scalar fields and a barotropic fluid in an FLRW-universe. The scalar potential is a sum of exponentials. All critical points are constructed and these include scaling and de Sitter solutions. A stability analysis of the critical points is performed for generalized assisted inflation, which is an extension of assisted inflation where the fields mutually interact. Effects in generalized assisted inflation which differ from assisted inflation are emphasized. One such a difference is that an (inflationary) attractor can exist if some of the exponential terms in the potential are negative.Comment: 27 page