Editing Uncertainty principle (section)

===Quantum field theory===

Some formulations of [[quantum field theory]] uses temporary electron–positron pairs in its calculations called [[virtual particles]]. The mass-energy and lifetime of these particles are related by the energy–time uncertainty relation. The energy of a quantum systems is not known with enough precision to limit their behavior to a single, simple history. Thus the influence of ''all histories'' must be incorporated into quantum calculations, including those with much greater or much less energy than the mean of the measured/calculated energy distribution.

The energy–time uncertainty principle does not temporarily violate [[conservation of energy]]; it does not imply that energy can be "borrowed" from the universe as long as it is "returned" within a short amount of time.<ref name="GriffithsSchroeter2018" />{{rp|145}} The energy of the universe is not an exactly known parameter at all times.<ref name=Sen2014/> When events transpire at very short time intervals, there is uncertainty in the energy of these events.