Quantum mechanics predicts the existence of what are usually called ''zero-point'' energies for the strong, the weak and the electromagnetic interactions, where ''zero-point'' refers to the energy of the system at temperature T=0, or the lowest quantized energy level of a quantum mechanical system. Although the term ''zero-point energy'' applies to all three of these interactions in nature, customarily (and hereafter in this article) it is used in reference only to the electromagnetic case.

Quantum mechanics predicts the existence of what are usually called ''zero-point'' energies for the strong, the weak and the electromagnetic interactions, where ''zero-point'' refers to the energy of the system at temperature T=0, or the lowest quantized energy level of a quantum mechanical system. Although the term ''zero-point energy'' applies to all three of these interactions in nature, customarily (and hereafter in this article) it is used in reference only to the electromagnetic case.