Q: In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.
Within a constant it's the Laplacian of the function "one over distance" and is also the charge density of a point charge. Actually an operator which projects out a function's value at the origin, it's not really a function at all. For ten points, name this mathematical entity, which is zero everywhere except the origin and is designated by a Greek letter.
A:
Science