A semiclassical singularity theorem

Understand

Quantum fields do not satisfy the pointwise energy conditions that are assumed in the original singularity theorems of Penrose and Hawking.

• Accordingly, semiclassical quantum gravity lies outside their scope.
• Although a number of singularity theorems have been derived under weakened energy conditions, none is directly derived from quantum field theory.
• Here, we employ a quantum energy inequality satisfied by the quantized minimally coupled linear scalar field to derive a singularity theorem valid in semiclassical gravity.