Who's afraid of naked singularities? Probing timelike singularities with finite energy waves - art. no. 104028

To probe naked spacetime singularities with waves rather than with particle s we study the well posedness of initial value problems for test scalar fie lds with finite energy so that the natural function space of initial data i s the Sobolev space. In the case of static and conformally static spacetime s we examine the essential self-adjointness of the time translation operato r in the wave equation defined in the Hilbert space. For some spacetimes th e classical singularity becomes regular if probed with waves while stronger classical singularities remain singular. If the spacetime is regular when probed with waves we may say that the spacetime is ''globally hyperbolic.'' [S0556-2821(99)00620-7].