Anti-de Sitter space bell. It might be described as being the "opposite" of the surface of a sphere, which has a positive curvature. General relativity is a theory of the nature of time, space and gravity in which gravity is a curvature of space and time that results from the presence of matter or energy. Energy and mass are equivalent (as expressed in the equation "E" = "mc"), and space and time can be translated into equivalent units based on the speed of light ("c" in the "E" = "mc" equation). A common analogy involves the way that a dip in a flat
Schrödinger equation a way to calculate the wave function of a system and how it changes dynamically in time. However, the Schrödinger equation does not directly say "what", exactly, the wave function is. Interpretations of quantum mechanics address questions such as what the relation is between the wave function, the underlying reality, and the results of experimental measurements. An important aspect is the relationship between the Schrödinger equation and wave function collapse. In the oldest Copenhagen interpretation, particles follow the Schrödinger equation "except" during wave function collapse, during which they behave entirely differently. The advent of quantum decoherence theory allowed alternative approaches