Braneworlds in Constant and Accelerated Motion and Their Causal Characteristics

Abstract

We generalize prior work on the signatures of bulk signals detected by brane-based observers in a spacetime with a compactified dimension. When such braneworlds move with constant velocities or constant proper accelerations in the extra dimension, the observers may witness apparent superluminal signaling. Our analysis includes tilted branes that are partially wrapped along the compact dimension. We identify parameters that help characterize various scenarios. Despite the apparent superluminality of bulk signals, we show that anisotropies in their propagation relative to the brane-based observer preserve causality. Some of the effects studied here could be the basis for alternative cosmological models, as well as observable signatures of braneworld scenarios.

Figures (17)

• Figure 1: Series of circles caused by the image charges in the preferred frame.
• Figure 2: Here we see the Isotropic wavefront generated on the Brane.
• Figure 3: Detection times for each signal $n$ given as a function of position x.
• Figure 4: Here, we see the general construction of the series of circles and their envelope at some given time $t"$.
• Figure 5: These are examples of the series of circles in a subcritical, critical, and supercritical frame at time $t{"}=0$. Here, we can see how the values of $\mathcal{E}$ affect the propagation of the image charges in the $x"-z"$ plane.