One-loop tunnelling-induced energetics

Tunnelling between degenerate vacuua is allowed in finite-volume Quantum Field Theory, and features remarkable energetic properties, which result from the competition of different dominant configurations in the partition function. We derive the one-loop effective potential based on two homogeneous vacuua of the bare theory, and we discuss the resulting Null Energy Condition violation in O(4)-symmetric Euclidean spacetime, as a result of a non-extensive effective action.