Figure 5: The left diagram corresponds to , with a subsequent causal structure which is divided into two regions by the curve. The end points of the worldsheet, denoted by , corresponds to two fundamental degrees of freedom with opposite charges. The right Penrose diagram corresponds to , and the resulting causal structure does not possess any event horizon. Dashed lines on both diagrams correspond to curves with constant . This diagram is taken from [77], with the authors’ consent.