Bubble needs strings

Abstract

In this paper, we want to emphasize the pivotal role played by strings in the model realizing de Sitter using an expanding bubble, proposed and subsequently developed in [1–3]. Contrary to the Randall-Sundrum model of brane-localized gravity, we use the end points of radially stretched strings to obtain matter sourcing gravity induced on the bubble wall. This allows us to reinterpret the possible volume divergence coming from naive dimensional reduction as mass renormalization in four dimensional particle physics. Furthermore, we argue that the residual time dependence in the bulk, pointed out by some recent work as a possible shortcoming of such models, is automatically cured in presence of these stringy sources.

Dark bubbles and black holes

“…where ρ = r + χ is the new radial coordinate. We also note that M = 3 χ /2 consistent with the results obtained in [8,9]. Note that the contribution from dz 2 / k 2 z 2 is sub-leading and does not contribute at this order.…”

“…As we will show in the next section, the solution contains a holographic "shadow" of the structure above the dark bubble, and the resulting picture will look like figure 1b. We will also see how the construction nicely generalizes the simpler examples studied in [8,9], where we made use of some techniques introduced in [17,20].…”

“…Our model was further studied in [7], where we showed, using a five dimensional bulk with stretched strings, how this will, through junction conditions generate an effective theory of four dimensional Einstein gravity on our dark bubble. In subsequent works, [8,9], we worked out how to imprint a Schwarzschild geometry on the dark bubble and the backreaction thereof on the bulk. For other aspects of these dark bubbles see, e.g., [10][11][12][13].…”

Tachyonic de Sitter Solutions of 10d Type II Supergravities

“…Such a realisation could match standard cosmological models described above, but alternative stringy approaches to cosmology have also been proposed (see e.g. [9–20] for a recent sample). Finding de Sitter solutions from string theory has been attempted for a long time, and the current situation is that it is difficult to build any well‐controlled example.…”

Battery Pot Plants with Magnets and Adjacent Balloon as Substitutes for Light

“…One way to characterise interaction with the balloon is gravity. Within cosmology, different kinds of modeling in multi-dimensions n, give a gravity measure Gn, proportional to gravity in a hyperspace, [10]. Between 5 and 4 dimensional spaces, two are G5=G4/k where k is a curvature and G5=G4×V5-4 where V5-4 is a compact space volume for the (5-4)th dimension.…”