Is it really naked? On cosmic censorship in string theory

We investigate the possibility of cosmic censorship violation in string theory using a characteristic double-null code, which penetrates horizons and is capable of resolving the spacetime all the way to the singularity. We perform high-resolution numerical simulations of the evolution of negative mass initial scalar field profiles, which were argued to provide a counterexample to cosmic censorship conjecture for AdS-asymptotic spacetimes in five-dimensional supergravity. In no instances formation of naked singularity is seen. Instead, numerical evidence indicates that black holes form in the collapse. Our results are consistent with earlier numerical studies, and explicitly show where the 'no black hole' argument breaks.

Figure 1

Coordinate choice.

Figure 2

Numerical evolution scheme.

Figure 3

Global structure of the spacetime resulting from the evolution of the truncated $1/r^2$ field profile (26) for the values of parameters $A=16$, $R_0=4$. Thick black lines on $m(x,t)$ plot show the locations of the apparent horizon and the singularity.

Figure 4

The size of the apparent horizon (left) and the reduced mass $\mu$ at the cut-off (right) for the same initial conditions as in Fig. 3. Solid and dashed lines show the values corresponding to Dirichlet and Neumann boundary conditions at the cut-off.

Figure 5

The size of the black hole formed in the collapse of the truncated $1/r^2$ field profile (26) as a function of parameters, shown for Dirichlet (left) and Neumann (right) boundary conditions at the cut-off.