Directional Quantum Singularities in Curzon Spacetime

The scalar quantum probe method developed by Horowitz and Marolf is applied to the cylindrically symmetric Curzon solution. The main cause for choosing the Curzon solution is that it is the best-known example that exhibits directional singularity. Interestingly the singularity at r=0, for the uncharged Curzon spacetime, which is classically very strong with a divergence rate of the order 1r10, becomes regular when examined using a scalar quantum field. The charged Curzon spacetime, however, due to the emergence of a second singularity off the r=0 singularity, does not regularize quantum mechanically. All three different charged versions, i.e., electric, magnetic, and dyonic, share the same feature.